Printed Circuit Board-Derived Glass Fiber-Epoxy Resin-Supported Mo

This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.

Article Cite This: ACS Omega 2018, 3, 18499−18509

http://pubs.acs.org/journal/acsodf

Printed Circuit Board-Derived Glass Fiber-Epoxy Resin-Supported Mo−Cu Bimetallic Catalyst for Glucose Synthesis Sourav Barman and Rajat Chakraborty* Department of Chemical Engineering, Jadavpur University, Kolkata 700032, India

ACS Omega 2018.3:18499-18509. Downloaded from pubs.acs.org by 185.89.100.143 on 01/06/19. For personal use only.

S Supporting Information *

ABSTRACT: A glass fiber-epoxy resin (GFER) framework derived from mixed waste printed circuit boards (MWPCBs) was utilized to prepare a cost-effective, reusable Mo−Cu bimetallic Bronsted−Lewis solid acid catalyst through wetimpregnation under near-infrared radiation (NIRR) activation. The efficacy of the novel Mo−Cu catalyst was assessed in the synthesis of glucose through hydrolysis of jute ( Corchorus olitorius) fiber, and the process parameters were optimized (Mo precursor loading: 1.0 wt %, catalyst concentration: 5 wt %, hydrolysis temperature: 80 °C, and hydrolysis time: 10 min) through Taguchi orthogonal design. The GFER support and the prepared catalysts were characterized through thermogravimetric, X-ray diffraction (XRD), Fouriertransform infrared (FTIR), Brunauer−Emmett−Teller (BET)−density functional theory, and TPD analyses. The optimal Mo− Cu catalyst and the GFER support possessed 45.377 and 7.049 m2/g BET area, 0.04408 and 0.02317 cc/g pore volume, 1.9334 and 0.7482 nm modal pore size, and surface acidity of 0.48 and 0.40 mmol NH3/g catalyst, respectively. X-ray photoelectron spectroscopy bands confirmed the coexistence of Mo6+ and Cu2+ species; XRD and FTIR analyses indicated the presence of MoO3 and CuO crystalline phases in all prepared catalysts. The optimal catalyst prepared through NIRR (wavelength 0.75−1.4 μm)-activated hydrothermal treatment resulted in a significantly greater glucose yield (75.84 mol %) than that achieved (53.64 mol %) using a conventionally prepared catalyst. Thus, an energy-efficient application of NIRR (100 W) could significantly improve catalytic properties over conventional hydrothermal treatment (500 W). The present investigation provides an innovative application of MWPCB-derived GFER as a promising cost-effective support for the preparation of highly efficient inexpensive solid catalysts for sustainable synthesis of glucose from low-cost waste jute fiber.

1. INTRODUCTION Printed Circuit Board (PCB) is an integral component of any electronic equipment as it electrically connects and mechanically supports other electronic components. According to Global E-waste Monitor 2017, globally 44.7 million metric tonnes of e-waste was generated,1 fueling concerns about the growing threats to the environment and public health. Waste PCBs are still being chiefly disposed in open air or in landfills that pose grave threat to the environment. Accumulation of waste PCBs is not only a crisis of quantity but also an alarming environmental concern because of the presence of toxic ingredients that results in occupational, environmental, and human health threats. Recovery and recycling of the metallic part from mixed waste PCBs (MWPCBs) drew the attention of many researchers because of the potential profitability through metal recovery; however, glass fiber-epoxy resin (GFER) which makes up around 65−70% of waste PCBs2 has been overlooked because of lesser economic value. Various separation processes of metal and nonmetallic ingredients of MWPCBs viz. physical recycling processes (e.g., shredding, hammer milling, ball milling, corona discharge separation, magnetic separation, eddy current separation, air classification, flotation, gravity separation, and density-based separation),3−6 © 2018 American Chemical Society

thermal processing (pyrolysis, gasification, and plasma treatment),7−9 hydrometallurgical processing,10,11 and solvent extraction (dimethyl sulfoxide, dimethyl formamide, Ndimethyl pyrrolidone, and ionic liquids)12−14 had been reported in last few decades. In recent years, hydrometallurgical processes attracted particular attention for the treatment of WPCBs. Several researchers reported the effectiveness of strong acids as a leachant for leaching of metals from waste PCBs; nevertheless, the generation of toxic gases (viz. Cl2, SO3, and NOx) and the acidic waste streams during the leaching process are detrimental to the environment. Jadhav et al.11 deployed a less hazardous organic acid viz. citric acid (0.5 M) along with hydrogen peroxide (1.76 M) as an effective leachant that rendered complete metal leaching to obtain GFER from a 4 × 4 cm2 WPCB in 4 h. Several scientific reports have been published on direct reutilization of GFER for the production of fuels (pyrolytic oil) and chemicals by thermal and catalytic pyrolysis; however, focus has been shifted toward the recovery of the GFER for alternative uses because of the low energy efficiency of the Received: October 11, 2018 Accepted: December 6, 2018 Published: December 27, 2018 18499

DOI: 10.1021/acsomega.8b02754 ACS Omega 2018, 3, 18499−18509

ACS Omega

Article

2. RESULTS AND DISCUSSION 2.1. Effects of Process Parameters on the PJF Hydrolysis Process. Table 1 represents individual ranks of

pyrolysis process. Although, various applications of GFER have been reported (e.g., as adsorbent and activated carbon),15−17 nonetheless, to date, the application of GFER as a costeffective support for the preparation of a metal-impregnated solid acid catalyst has not been reported. Notably, hydrolysis of lignocellulosic biomass (LB) for maximization of monosaccharide yield in a sustainable way is one of the most investigated arenas. Jute fiber [65−70 wt % cellulose 20−25 wt % hemicellulose and 10−12 wt % lignin]18 could be exploited as a feedstock for hydrolytic conversion into glucose because of its high cellulosic content. Very scanty works have been reported on jute hydrolysis for glucose production. Roy et al.19 obtained a maximum of 50% yield of a reducing sugar from pretreated jute powder using immobilized enzymes, while Matsagar et al.20 reported 86% furfural yield from jute employing 1-methyl-3(3-sulfopropyl)-imidazolium hydrogen sulfate ([C3SO3HMIM][HSO4]) brønsted acidic ionic liquid catalyst at 433 K and 1 h. Evidently, inadequate research studies have been performed on glucose production from jute fiber notwithstanding its high cellulose content. LB can be hydrolyzed using a homogeneous 21 or heterogeneous acid catalyst to obtain important platform chemicals which can be further treated to generate biofuel and value-added chemicals.22,23 However, in recent years, heterogeneous acid catalysts have been observed to be advantageous over homogeneous catalysts owing to convenience of product separation, less corrosiveness, and minimal waste stream generation.24 Heterogeneous catalysts such as supported metal oxides can be catalytically active for cellulose conversion.25−27 Takagaki et al.25 demonstrated water-tolerant HNbMoO6 catalyst for the production of glucose from saccharides. A study revealed that 0.2 g of HNbMoO6 catalyst can render 24.1 mmol g−1 glucose from sucrose in 1 h and 373 K, whereas 6.6 mmol g−1 glucose was produced using the commercial Amberlyst-15 catalyst. Another work reported by Hegner et al.26 revealed that Nafion and FeCl3 supported on amorphous silica could produce glucose with a maximum yield of 9% from cellulose at 463 K in 24 h. Thus, it can be perceived that although supported metal oxide acid catalysts are efficient, nevertheless, hydrolysis of LB requires severe reaction conditions. Accordingly, several researchers investigated the application of microwave radiation (350 W)28 and ultrasonication (750 W)29 to augment the hydrolysis reaction; still these require high energy input, which in turn makes the overall process economically ill favored. Applications of waste-supported photocatalysts30 and bimetallic photocatalysts31 in photodegradation of organic pollutants and water splitting were reported by several researchers, although very scanty works on biomass hydrolysis have been found.32 This article primarily envisages the preparation of a catalyst support (GFER, containing Cu) from WPCBs using less a hazardous organic acid (viz. acetic acid) instead of using conventional toxic mineral acids (e.g., HCl and H2SO4). A highly proficient and cost-effective Mo−Cu-doped GFERsupported solid acid catalyst was prepared by an energyefficient near-infrared radiation (NIRR)-activated hydrothermal treatment through functionalization of GFER with [CH3COCHC(O−)CH3]2MoO2. The efficacy of the prepared novel catalyst has been estimated through optimization [by Taguchi orthogonal design (TOD)]33 of pretreated jute fiber (PJF) hydrolysis under NIRR to maximize glucose selectivity.

Table 1. S/N Ratios and Δ of Process Parameters in Pretreated Jute Hydrolysis

a

level

ϕNIRRMo (wt %)

ϕMoC (wt %)

ϕTNIRR (°C)

ϕtNIRR (min)

1 2 3 delta (Δ) rank

34.45 36.40a 36.36 1.95 1

35.33 36.02a 35.85 0.70 3

34.80 35.77 36.63a 1.83 2

35.75a 35.73 35.72 0.03 4

Larger is better.

process parameters affecting the response variable (GNIRR) based on Δ-values and SN ratios, where the factor corresponding to the maximum Δ-value has been ranked 1. Furthermore, from analysis of variance (Table S1) for the jute hydrolysis process, it can be observed that the hydrolysis temperature (ϕTNIRR) and Mo precursor loading (ϕNIRRMo) were statistically significant process variables at 95% confidence level (p-value < 0.05). Thus, from Table 1, it may be concluded that L0 of ϕNIRRMo (1.0 wt %), L0 of ϕMoC (5 wt %), L1 of ϕTNIRR (80 °C), and L−1 of ϕtNIRR (10 min) were the optimum process values rendering maximum glucose yield. 2.2. Interactive Effects of Process Parameters on PJF Hydrolysis. Parametric interaction for the PJF hydrolysis process has been depicted in Figure 1. Interaction between Mo loading and catalyst concentration (remaining two parameters at the optimum level) revealed that an increment in Mo precursor loading resulted in a higher glucose yield (GNIRR) [Figure 1A] at all levels of catalyst concentration, which clearly suggested that the prepared Mo−Cu-impregnated GFER catalyst immensely favored PJF conversion. A similar trend was observed for all values of catalyst concentration. From, Figure 1(B) it can be concluded that the hydrolysis process was endothermic in nature as the hydrolysis temperature monotonically enhances GNIRR. On the other hand, hydrolysis time has an antagonistic effect on GNIRR because of the degradation of glucose at higher hydrolysis time Figure 1E. The individual parametric effect on GNIRR has been presented in the Supporting Information (Figure S1). 2.3. Catalyst Characterization. 2.3.1. Thermogravimetric Analysis. The thermogravimetric (TGA) patterns (Figure 2) of MWPCB powder, GFER, CCu−Mo1.0, and NCu−Mo1.0 manifest the thermal stability and decomposition of samples on heating over a range of temperature from 30 to 500 °C. The TGA thermogram of MWPCB and GFER shows a major weight loss (35%) over 280−450 °C, which is ascribed to the degradation of epoxy resin. Furthermore, thermal decomposition of GFER was faster compared to MWPCB powder because of the chemical treatment (shown in FTIR spectroscopy). On the other hand, relatively less weight loss occurred in NCu−Mo1.0 and CCu−Mo1.0 because of the ionic polymerization of epoxy resin. Moreover, the TGA plot of NCu−Mo1.0 reveals a weight loss of 2 wt % over 220−250 °C, which corresponds to the decomposition of the precursor, that is, bis(acetylacetonato)dioxomolybdenum(VI) (decomposition temperature 228−229 °C), that leads to the liberation of carbon oxides, acetone, methane, and isobutene.34 Notably, NCu−Mo1.0 shows better thermal stability compared to CCu− Mo1.0, which reveals better thermal activation of NIRR over 18500


ACS Omega

Article

Figure 1. Interaction plots for the PJF hydrolysis process parameters: (A) catalyst concentration vs Mo loading; (B) hydrolysis temperature vs Mo loading; (C) hydrolysis time vs Mo loading; (D) hydrolysis temperature vs catalyst concentration; (E) hydrolysis time vs catalyst concentration; and (F) hydrolysis time vs hydrolysis temperature.

Figure 2. TGA analysis of MWPCB, GFER, NCu−Mo1.0, and CCu− Mo1.0.

conventional hydrothermal treatment in catalyst preparation. Thus, 240 °C was selected as the calcination temperature to prepare the GFER-supported Cu−Mo catalyst to avoid degradation of epoxy resin. Notably, as the hydrolysis temperature was appreciably lower (60−80 °C) than the calcination temperature, thermal decomposition of the developed catalysts is unlikely during the hydrolysis process. 2.3.2. X-ray Diffraction. Figure 3 depicts the X-ray diffraction (XRD) patterns for GFER powder and calcined samples [Mo-free GFER, NCu−Mo0.75, NCu−Mo1.0, NCu− Mo1.25, and CCu−Mo1.0]. Peaks representing the crystalline phase of copper oxide (37.264°, 43.303°, and 48.799°),35 molybdenum trioxide (13.76°),36 and molybdenum disilicide (29.94°) were detected for all catalysts. The diffraction patterns evidence the presence of copper (43.28°, 50.39°, and 74.12°)35 in GFER powder, which is attributed to the existence of copper oxide in all catalysts and calcined Mo-free GFER samples. Notably, with increasing [CH3COCH C(O−)CH3]2MoO2 loading (Figure 3), the prominence of MoO3 and MoSi2 peaks gradually increases in the NCu−Mo catalyst which in turn increases the acidity of the catalyst. Furthermore, the presence of a more intense peak of molybdenum trioxide was also found in NCu−Mo1.0 and NCu−Mo1.25 compared to CCu−Mo1.0. 2.3.3. FTIR Spectroscopy. Fourier transform infrared (FTIR) analysis of GFER and all catalyst samples shows prominent peaks of OH stretching located at 3568.12 cm−1 because of the formation of hydroxyl-containing silanol groups, which signifies the porous structure of the samples.37

Figure 3. Powder XRD pattern of (A) GFER powder, (B) Mo-free calcined GFER powder, (C) NCu−Mo0.75, (D) CCu−Mo1.0, (E) NCu−Mo1.0, and (F) NCu−Mo1.25 [characteristic peaks due to CuO ( ), MoO3 ( ), MoSi2 ( ), SiO2 ( ), and Cu ( )].

Vibrations regarding the C−H stretch of aromatic and alkane groups are observed at wavelengths 3058.89 and 2970.13 cm−1, respectively.37 Other adsorption peaks at 1454 and 1510.41 cm−1 are also assigned to the stretching vibration of C−C and C−H bands of alkane and aromatic38 groups, respectively (Figure 4A). On other hand, the intensity of the strong band located at 2970.13 cm−1 in the GFER support has been significantly reduced after calcination at 240 °C (Figure 4). Furthermore, reduction of absorption peaks at 1760.23 and 1660.65 cm−1 (symmetric stretching of the epoxy ring) for the catalyst samples suggests the ring-opening cleavage of the epoxy groups by [CH3COCHC(O−)CH3]2MoO2.39 Furthermore, the vibration at 996.71 cm−1 in the catalyst samples indicates the presence of Mo which gradually increases with Mo precursor loading.40 2.3.4. NH3-TPD. Figure 5 shows several NH3-TPD peaks within the temperature range of 150−260 °C for the catalyst and calcined GFER samples. The presence of weak acidic sites in all samples at 215 °C is ascribed to Cu2+ ions,41 whereas 18501


ACS Omega

Article

hydrothermal activation during catalyst preparation compared to the conventional heating protocol. 2.3.5. FTIR-Pyridine. The nature of the acid sites of NCu− Mo1.0, CCu−Mo1.0, and calcined GFER has been further studied by FTIR-pyridine analysis (Figure 6). The presence of

Figure 6. IR spectra of pyridine adsorption of (A) calcined GFER, (B) CCu−Mo1.0, and (C) NCu−Mo1.0.

Figure 4. FTIR analysis of (A) GFER, (B) NCu−Mo0.75, (C) CCu− Mo1.0, (D) NCu−Mo1.0, and (E) NCu−Mo1.25.

absorption peaks of a pyridinium ion at 1538 and 1447 cm−1 for calcined GFER is attributed to the Bronsted acid and Lewis acid sites, respectively.44 The spectrum of NCu−Mo1.0 and CCu−Mo1.0 catalysts also shows bands at 1538 (Bronsted site) and 1447 cm−1 (Lewis site) along with a band at 1488 cm−1 that is assigned to the intermediate Bronsted and Lewis acid sites.45 From Figure 6, it can be seen that the Bronsted acid capacity of NCu−Mo1.0 and CCu−Mo1.0 increases compared to calcined GFER, which may be due to the development of polymolybdate Keggin structures.46 Furthermore, under NIRR, relocation and dispersion of active sites (Mo6+ and Cu2+)47 occur that create new pores in the GFER framework, which eventually act as Bronsted acid centers owing to the presence of water. Bronsted acidic sites are beneficial to LB hydrolysis for conversion to glucose.48 Notably, NIRR also stimulates inaccessible Cu2+ to come out from the internal surface to the exterior of the catalyst,47,49 thus rendering more accessibility to Cu2+, which in turn increases Lewis acidity and thus overall acidity. Consequently, increment in overall acidity could be achieved in the case of the NIRR-radiated catalyst compared to the conventionally prepared catalyst. 2.3.6. Brunauer−Emmett−Teller Analysis. Brunauer− Emmett−Teller (BET) analysis method was employed to determine the specific surface area of the catalysts and GFER support. Table 2 demonstrates the substantial increase of the specific surface area of the optimal NCu−Mo1.0 catalyst (45.377 m2/g) compared to the GFER support (7.049 m2/g). During the calcination step, liberation of carbon oxides, acetone, methane, and isobutene created new pores in the catalyst matrix, which in turn enhanced the surface area of the

Figure 5. NH3-TPD analysis of the prepared catalysts and calcined GFER.

acidic peaks positioned above 235 °C have been assigned to Mo6+ ions.42 Moreover, with Mo precursor loading, the presence of new acidic-site peaks was observed in all catalyst samples, whose intensity increases with Mo precursor loading up to 1.0 wt %. Decrease in acidity of the NCu−Mo1.25 catalyst may be due to the substantial loss of Bronsted acidic sites on the GFER surface as Mo6+ replaces the Bronsted acidic sites.43 Notably, at 1.0 and 1.25 wt % precursor loading, NIRRactivated catalysts shows higher acidity compared to CCu− Mo1.0 (Table 2), which advocates that NIRR has caused better

Table 2. Effects of Mo Precursor Loading on Specific Surface Area and Acidity on the Prepared Catalyst BET analysis Mo precursor loading 0.75

NCu−Mo NCu−Mo1.0 NCu−Mo1.25 CCu−Mo1.0

surface area (m2/g)

total pore volume (cc/g)

pore diameter (nm)

NH3-TPD (mmol NH3/g catalyst)

GFIR yield (%)

32.841 45.377 39.624 23.841

0.04082 0.04408 0.04153 0.03328

1.8760 1.9334 1.6725 1.1610

0.37 0.48 0.42 0.40

61.43 75.84 69.38 53.64

18502


ACS Omega

Article

NCu−Mo1.0 catalyst; the results of the present study corroborate well with the findings of El-Molla et al.50 The shape of the adsorption isotherm of the optimal catalyst NCu− Mo1.0 corroborates type I isotherm (IUPAC) (Figure 7)

Figure 9. SEM images of the NCu−Mo1.0 catalyst at different magnifications [(A) 10; (B) 5 μm].

GFER, a clear contrast enhancement was found in Figure 10B,C as compared to Figure 10A. A careful inspection of Figure 10A−C reveals the transformation of surface morphology; NCu−Mo1.0 possesses more porous structures in comparison with GFER and CCu−Mo1.0. The high-resolution TEM (HRTEM) image (Figure 11A) of the NCu−Mo1.0 catalyst exhibits the presence of MoO3 and CuO crystallites by white and red rectangles, respectively. The lattice spacing of 0.231 nm corresponds to the (111) plane of CuO crystallites (JCPDS: no. 48-1548) (indicated by the inclined lines in Figure 11B) while the lattice spacing of 0.63 nm represents the (020) plane of MoO3 (indicated by the inclined lines in Figure 11C). 2.3.9. X-ray Photoelectron Spectroscopy. Figure 12 displays the X-ray photoelectron spectroscopy (XPS) diagram of the Taguchi-derived optimum NCu−Mo1.0 catalyst for the jute hydrolysis process (A and B). XPS spectra detect two doublets at 234.67 and 237.84 eV corresponding to Mo6+ 3d3/2 and Mo6+ 3d5/2, respectively.51 The preceding peaks indicate the higher oxidation state of Mo (MoO3) in the prepared NCu−Mo1.0 catalyst. In Figure 12B, the XPS spectra depict that Cu 2p3/2 (II) lies at 936.76 eV and with one shake-up satellites at a higher binding energy 944.84 eV, which is attributed to CuO.52 Considering these observations, it might be concluded that Cu2+ species existing in the prepared NCu− Mo1.0 enhanced the catalyst acidity (0.48 mmol NH3/g catalyst) vis-à-vis catalytic activity. From the experimental result of PJF hydrolysis (Table 4), it may be inferred that an increase in the Mo precursor up to 1.0 wt %, that is, [CH3COCHC(O−)CH3]2MoO2 loading could improve the catalytic performance, which signifies that Mo6+ detected in XPS analysis was the major active phase in the PJF hydrolysis process to yield glucose. 2.3.10. Reaction Mechanism. The Mo6+ and Cu2+ active phases present in the prepared catalyst (NCu−Mo1.0) both behave as Lewis acid, whereas Bronsted acidic sites were also present on the prepared catalyst surface.43 Additionally, Mofree calcined GFER has resulted in 44.36 mol % GNIRR yield, whereas when a Mo6+ ion was introduced in the GFER framework, the resultant catalyst renders a remarkably higher GNIRR yield (75.84 mol %). The catalytic hydrolysis mechanism of PJF was depicted in Figure 13, which suggests that initially water molecules (0.275 nm) are adsorbed on the catalyst surface (pore dia. 1.9334 nm) and form a hydronium ion which in turn resulted in the formation of H+ and OH− ions. Notably, cellulose molecules did not adsorb on the catalyst surface which is attributed the fact that the H+ ion attacks the cellulosic structure (1,4-β glycosidic linkage) which leads to the formation of glucose molecules. 2.3.11. Catalytic Performance of the NCu−Mo1.0 Catalyst on the PJF Hydrolysis Process. To understand the efficacy of

Figure 7. Pore volume vs relative pressure (P/P0) of the optimum catalyst NCu−Mo1.0 [inset: DFT pore size distribution for the determination of modal pore diameter].

implying monolayer adsorption. Density functional theory (DFT) method was employed to evaluate the NCu−Mo1.0 catalyst pore volume (0.04408, 0.02317 cc/g for GFER) and modal pore diameter (1.9334, 0.7482 nm for GFER) (inset of Figure 7). Furthermore, from Figure 8, it can be observed that

Figure 8. Cumulative pore volume vs pore diameter for the NCu− Mo1.0 catalyst.

51.11% micropores and 48.89% mesopores were present in the NCu−Mo1.0 catalyst. Notably, as the size of the water molecules were smaller (0.275 nm) than the pore diameter of the NCu−Mo1.0 catalyst, adsorption of water molecules easily occurred on the surface of the developed catalysts which augmented the hydrolysis reaction. 2.3.7. Scanning Electron Microscopy. The scanning electron microscopy (SEM) images of the optimum NCu− Mo1.0 catalyst after calcination at 240 °C are depicted in Figure 9, which shows irregular rod-shaped fiber glass particles partially surrounded by epoxy resin. Microscopic observation suggests that the formation of Lewis acidic sites and Bronsted acidic sites occurred on the partially exposed fiber glass surface. 2.3.8. Transmission Electron Microscopy Analyses. The morphology of GFER, NCu−Mo1.0, and CCu−Mo1.0 was further investigated by transmission electron microscopy (TEM) analysis (Figure 10). With Mo precursor doping to 18503


ACS Omega

Article

Figure 10. TEM images of (A) GFER; (B) CCu−Mo1.0; and (C) NCu−Mo1.0.

Furthermore, from Figure 14, it can be observed that Amberlyst-15 renders better GNIRR yield compared to CCu− Mo1.0 after 5 min of hydrolysis reaction, which may be due to the leaching of −SO3H group from the Amberlyst-15 framework55 (acts as a homogeneous catalyst). Notably, it should be also mentioned that the optimum glucose yield (75.84 mol %) was much higher compared to the yield reported in the previous work (50 mol %).19 2.4. Hydrolysate Characterization. 2.4.1. FTIR Analyses of the Hydrolysate. The hydrolysate obtained from PJF hydrolysis at the optimum condition was analyzed through FTIR spectroscopy and compared with the characteristic peaks of standard glucose. A prominent peak at 3424.18 cm−1 was attributed to the stretching vibrations of O−H group56 while stretching vibrations at 2965.51 and 2936.85 cm−1 confirm the presence of CH groups.57 Additionally, the presence of H−C− H group was observed at 1422.36 and 1463.45 cm−1. The peaks at 1618.32 and 1206.68 cm−1 could be ascribed to CC and C−O−C bonds, respectively.58 Furthermore, the peaks at 744.62 and 610.87 cm−1 indicated the presence of few aromatic functional groups. 59 Thus, Figure 15 clearly manifested that these infrared spectra indicate the existence of representative functional groups of glucose in the hydrolysate. Moreover, higher intensity of infrared spectra for the hydrolysate obtained from NCu−Mo1.0-hydrolyzed PJF compared to the hydrolysate for CCu−Mo1.0 indicates the efficacy of the NCu−Mo1.0 catalyst over CCu−Mo1.0. 2.4.2. HPLC Analyses of Hydrolysates. The hydrolysate obtained from NCu−Mo1.0- and CCu−Mo1.0-catalyzed PJF hydrolysis at an optimal condition was quantified by employing high-performance liquid chromatography (HPLC) (Figure 16). Hydrolysate constituents such as 5-HMF, xylose, and glucose were retained at 23.83, 9.84, and 9.26 min, respectively.60,61 The glucose concentration was remarkably higher (68 wt %) compared to 5-HMF (12 wt %) and xylose

Figure 11. HRTEM image of (A) NCu−Mo1.0; (B) magnified view of the red rectangle section [inset shows the fast Fourier transform (FFT) of the enclosed region]; and (C) magnified view of the white rectangle section [inset shows the FFT of the enclosed region].

the optimum NCu−Mo1.0 catalyst, hydrolysis of the PJF was also conducted using calcined GFER, CCu−Mo1.0, and commercial catalyst Amberlyst-15 (surface area: 45 m2/g, pore size: 25 nm, acidity: 4.8 mmol/g catalyst) at the TODderived optimal condition. NCu−Mo1.0 shows better activity in terms of glucose yield (75.84 mol %) over Amberlyst-15 (GNIRR: 61.53 mol %); CCu−Mo1.0 (GNIRR: 53.64 mol %) and calcined GFER (GNIRR: 38 mol %). The high catalytic activity of NCu−Mo1.0 over Amberlyst-15 can be attributed to the light-absorbing ability of the prepared catalyst due to the presence of CuO and MoSi2.53,54 The UV−vis spectra of NCu−Mo1.0 exhibit a UV absorption peak (200−400 nm) in addition to an absorption hump within the visible range (between 550 and 700 nm) of electromagnetic spectra (Figure S2). PJF hydrolysis conducted under conventional heating (500 W) using NCu−Mo1.0 rendered maximum 63.16 mol % glucose yield in comparison with 75.84 mol % obtained under NIRR at the TOD-derived optimal condition. Thus, the light absorbing ability of the prepared catalyst was evident.

Figure 12. XPS spectra of the (A) Mo 3d and (B) Cu 2p of the NCu−Mo1.0 catalyst. 18504


ACS Omega

Article

Figure 13. Proposed PJF hydrolysis mechanism on the NCu−Mo1.0 catalyst.

Figure 14. Catalytic performance of NCu−Mo1.0, calcined GFER, CCu−Mo1.0, and Amberlyst-15 in the PJF hydrolysis process.

Figure 16. HPLC of the hydrolysate obtained from (A) NCu−Mo1.0catalyzed hydrolysis and (B) CCu−Mo1.0-catalyzed hydrolysis of PJF at optimum process conditions.

condition. After each hydrolysis step, the catalyst was easily recovered by screening (mesh size: 200 μm) the oven-dried (at 105 °C for 1.5 h) hydrolysis residue. The hydrolysate yield decreased from 75.84 to 71.39% after fourth recycle (fifth batch) while no further decrease in glucose yield was observed in subsequent three more reaction cycles. Inductively coupled plasma (ICP)-optical emission spectroscopy of the reused catalyst reveals that an insignificant amount of active sites (0.11 ppm) has been leached from NCu−Mo1.0, while CCu− Mo1.0 suffered leaching up to 1.76 ppm, which corroborates well with the results of Zhao et al.;51 this further reinforces the superiority of NIRR over CH.

Figure 15. FTIR analyses of (A) standard glucose; hydrolysate obtained from (B) NCu−Mo1.0-catalyzed hydrolysis; and (C) CCu− Mo1.0-catalyzed hydrolysis at optimum process conditions.

(21 wt %) for the NCu−Mo1.0-catalyzed PJF hydrolysis process. 2.5. Catalyst Reusability. The reusability of the prepared optimal catalyst NCu−Mo1.0 was evaluated by taking seven consecutive experimental runs at the optimal PJF hydrolysis

3. CONCLUSIONS Waste PCB-derived epoxy-glass fiber (GFER)-supported Mo− Cu Bronsted−Lewis acid catalysts can be developed employing both NIRR and conventional hydrothermal treatment. The 18505


ACS Omega

Article

Figure 17. Flow Chart for MWPCB processing.

precursor loading 1.25 wt %). Furthermore, to assess the effect of NIRR on catalytic properties, a GFER-supported Cu−Mo catalyst was also prepared through conventional hydrothermal treatment (500 W) at optimum (1 wt %) loading and designated as CCu−Mo1.0, and its performance has been evaluated in the jute hydrolysis reaction. Thus, NIRR consumed 80% less energy compared to conventional heating in hydrothermal treatment. 4.4. Characterization of GFER and the Prepared Catalyst. TGA analysis of the MWPCB, oven-dried GFER powder, calcined GFER, and prepared Mo−Cu catalyst was performed with a PerkinElmer TGA analyzer (Pyris Diamond TG/DTA) in a nitrogen atmosphere (20 mL/min) from 30 to 500 °C with a temperature increase rate of 15.0 °C/min. The infrared spectra of the MWPCB, GFER powder, calcined GFER, and prepared Mo−Cu catalyst were detected with FTIR-SHIMADZU (Alpha), from 400 to 4000 cm−1, while the XRD patterns of the samples were analyzed using a Cu Kα source equipped with an Intel CPS 120 hemispherical detector. XRD Analysis was performed at 2θ ranging from 10° to 90° at a scanning speed of 1° min−1. The specific surface area, pore volume, and pore size distribution were measured by BET and DFT methods using Quantachrome Instruments, Nova 4000e. Before BET−DFT analysis, the samples were pretreated and degassed at 150 °C to remove surface moisture. The acidity of the catalysts and calcined GFER was determined through NH3-TPD experiments using Quantachrome Instruments, TPR win v2.1. Furthermore, the Bronsted and Lewis acidic sites of the optimum catalyst and calcined GFER were evaluated by FTIR spectrometry.62 The samples (30 mg) were pressed into self-supporting discs (diameter 1.2 cm) and outgassed under vacuum (10−5 mbar) at 200° C for 2 h. Adsorption of pyridine on the outgassed samples was saturated at a pressure of 5 mbar for 10 min, and after adsorption of pyridine, the samples were further outgassed under vacuum at 100 °C for 30 min to remove the physiosorbed pyridine. The binding energy of Mo 3d and Cu 2p of the optimum catalyst was measured by XPS, while surface morphology of the optimum catalyst was determined using SEM at 15 kV (JEOL Ltd., JSM-6360). Additionally, TEM and high-angle annular dark-field scanning TEM (HAADF−STEM) analysis were carried out also on a FEI Titan G2 60 -300 transmission electron microscope at an accelerating voltage of 300 kV. The lattice spacing of the crystallites was calculated using a “GATAN digital micrograph” through processing the micrographs. The photocatalytic property of the optimum NCu− Mo1.0 catalyst and calcined GFER was verified with a PerkinElmer Lamda-365 UV−visible spectrophotometer in the range 200−900 nm.63 4.5. Reactor Configurations and Hydrolysis Procedure. The performance of the prepared NCu−Mo catalyst was

NIRR-promoted catalyst shows superiority over conventional hydrothermal-treated catalyst in terms of catalytic properties and glucose yield in the jute fiber hydrolysis process. Effects of process factors on glucose yield have been studied using analysis of variance and optimized through TOD. The waste PCB-derived GFER could be used as a catalyst support to produce the cost-effective Mo−Cu catalyst. Thus, waste PCBs can be effectively exploited in developing reusable, highly efficient supported acid catalyst, hence creating another an effective avenue of e-waste valorization for the generation of value-added chemicals from LB.

4. EXPERIMENTAL SECTION 4.1. Chemicals and Materials. Bis(acetylacetonato)dioxomolybdenum(VI) [[CH3COCHC(O−)CH3]2MoO2], acetic acid, hydrogen peroxide, acetone, DNS (dinitro salicylic acid), aqueous NH4OH (25%), and so forth were purchased from Merck, and all chemicals used were of analytical reagent grade. The MWPCBs were collected from a local scrap market at Kolkata, India. The Jute fiber was also purchased from a local market. 4.2. MWPCB Processing. The attached parts, viz. RAM, PCI slot, and chip slots were removed manually from the collected MWPCB (computer, TV, other electrical, and electronics component), and the MWPCB was ground into fine powder (150 μm mesh size) using a drum sander and laboratory ball mill. Afterward, the ferrous materials were removed using a magnetic stirrer. Subsequently, 1 M NaOH solution was added for the removal of tin, aluminum, and lead through sedimentation. Powder MWPCB (5 g) was stirred with 100 mL of 1 M NaOH solution for 4 h at 50 °C for the complete removal of tin, aluminum, and lead. Then, the glass fiber, epoxy resin, and copper mixture were separated and collected and sent for oven drying. Afterward, copper was removed by stirring the NaOH-treated MWPCB with 100 mL of 1 M acetic acid and 10 mL of H202 solution for 4 h. Finally, the glass fiber, epoxy resin, namely, the nonmetallic part (GFER) was collected and oven-dried (105 °C) and eventually used for catalyst preparation (Figure 17). 4.3. Catalyst Preparation. With a measured amount of prepared dry powder GFER [containing Cu (0.65 wt %; measured by ICP)] from MWPCB, varying precursor loads of [CH3COCHC(O−)CH3]2MoO2 were added, and the mixture was stirred vigorously in acetone for 4 h at 60 °C under NIRR (100 W; near-infrared wavelength: 0.75−1.4 μm). Subsequently, the mixture was ripened for 24 h and eventually oven-dried (105 °C). Afterward, Mo-dispersed GFER was calcined at 240 °C for 3 h, and accordingly, GFER-supported Cu−Mo catalysts prepared through NIRR were designated as NCu−Mo0.75 (Mo precursor loading 0.75 wt %), NCu−Mo1.0 (Mo precursor loading 1.0 wt %), and NCu−Mo1.25 (Mo 18506


ACS Omega

y jij 1 r 1 zzz zz S/N = −10 logjjj ∑ 2 jj r j = 1 G NIRR, j zz k {

evaluated in the jute hydrolysis process. One-pot pretreatmenthydrolysis of jute fiber was performed in a batch reactor assisted with an NIRR (100 W; 0.75−1.4 μm) system. For pretreatment, a measured amount of jute fiber was taken in a three-neck flask, followed by addition of a measured amount of aqueous NH4OH (2.5 mL/g of jute fiber) and deionized water (20 mL/g of jute fiber) at a preset controlled temperature of 70 °C. Over the specified time span of 20 min, the mix was stirred at 400 rpm. After pretreatment, the purging of N2 through one neck of the three-neck flask was carried out to remove remaining ammonia. Afterward, a measured amount of the prepared catalysts and water (10 mL/g of jute fiber) was added to the PJF present in the reactor mix and stirred at 400 rpm for the subsequent hydrolysis over a specified time (Table 3). Subsequently, vacuum filtration was conducted to separate

ϕNIRRMo (wt %)

ϕMoC (wt %)

ϕTNIRR (°C)

ϕtNIRR (min)

L−1 L0 L1

0.75 1.0 1.25

2.5 5 7.5

60 70 80

10 15 20

■

ϕNIRRMo (wt %)

ϕMoC (wt %)

ϕTNIRR (°C)

ϕtNIRR (min)

GNIRR

Std.

S/N ratio

1 2 3 4 5 6 7 8 9

L−1 L−1 L−1 L0 L0 L0 L1 L1 L1

L−1 L0 L1 L−1 L0 L1 L−1 L0 L1

L−1 L0 L1 L0 L1 L−1 L1 L−1 L0

L−1 L0 L1 L1 L−1 L0 L0 L1 L−1

45.30 54.81 59.20 63.17 75.84 60.10 69.57 60.94 67.10

±0.21 ±0.11 ±0.04 ±0.17 ±0.08 ±0.33 ±0.09 ±0.22 ±0.15

33.12 34.78 35.45 36.01 37.60 35.58 36.85 35.70 36.53

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsomega.8b02754. Information on analysis of variance (ANOVA) of the PJF hydrolysis process factors; main effect plots for PJF hydrolysis at the optimal condition; UV−vis spectra of NCu−Mo1.0 and GFER; and HAADF-STEM analysis of NCu−Mo1.0 (PDF)

Table 4. TOD Layout for PJF Hydrolysis Using NCu−Mo Catalystsa runs

(1)

where r is the number of experimental runs performed at a particular set condition (Table 4), j is the number of replications, and GNIRR,j is GNIRR corresponding to run r. 4.7. Physicochemical Characterization of the Hydrolysate. Hydrolysate concentrations were evaluated by the DNS method.64 The compositional analysis of the hydrolysate was performed by HPLC with an RI detector (PerkinElmer 200 Series) along with a 300 × 7.8 mm Bio-Rad HPXP, 9 μm column and 0.005 M sulfuric acid as the mobile phase (flow rate: 0.6 mL min−1). The hydrolysate constituent concentrations were quantified from the calibration plots of respective standard constituents. The infrared spectra of the liquid hydrolysate were also analyzed by FTIR spectroscopy (FTIRShimadzu Alpha, from 400 to 4000 cm−1).

Table 3. Process Variable for PJF Hydrolysis Using NCu− Mo Catalysts process variable

Article

■

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected], rajat_chakraborty25@yahoo. com. Phone: +91 3324572689, +91 3324146378. Fax: +91 3324572689, +91 3324146378. ORCID

Rajat Chakraborty: 0000-0002-4599-135X

a

L−1: lower level; L0: middle level; L1: upper level.

Notes

The authors declare no competing financial interest.

■ ■

ACKNOWLEDGMENTS The first author gratefully acknowledges the financial support of DST Purse Phase-II Fellowship, Government of India.

the jute fiber residue and the catalyst. Afterward, the filtrate was processed for the measurement of glucose concentration by a standard DNS method. Moreover, to identify the efficacy of optimum NCu−Mo catalysts over CCu−Mo and Amberlyst-15 on hydrolysis, pretreated jute was hydrolyzed using these catalysts at the otherwise TOD-predicted optimal condition. The hydrolysate was analyzed for glucose yield to compare with that of catalytic hydrolysis. 4.6. Design of the Experiment. The efficacy of the prepared catalysts was tested in the PJF hydrolysis reaction deploying the following four independent process factors viz., Mo loading (ϕNIRRMo), catalyst concentration (ϕMoC ), hydrolysis temperature (ϕTNIRR), and hydrolysis time (ϕtNIRR). Using L9 TOD (Minitab Inc. USA for Windows 7), nine experimental runs (Table 4) were conducted to assess and optimize the effects of independent process factors on the response variable (glucose yield, GNIRR). The optimal process factors corresponding to maximum GNIRR were determined through evaluation of signal-to-noise (S/N) ratios (employing the “larger is better” criterion) (eq 1) and analysis of variance (ANOVA).

REFERENCES

(1) Balde, C. P.; Forti, V.; Gray, V.; Kuehr, R.; Stegmann, P. The Global e-Waste Monitor 2017: Quantities, Flows and Resources; United Nations University, International Telecommunication Union, and International Solid Waste Association, 2017. (2) de Marco, I.; Caballero, B. M.; Chomón, M. J.; Laresgoiti, M. F.; Torres, A.; Fernández, G.; Arnaiz, S. Pyrolysis of electrical and electronic wastes. J. Anal. Appl. Pyrolysis 2008, 82, 179−183. (3) Eswaraiah, C.; Soni, R. K. Milling and Classification of Printed Circuit Boards for Material Recycling. Part. Sci. Technol. 2015, 33, 659−665. (4) Li, J.; Xu, Z.; Zhou, Y. Application of corona discharge and electrostatic force to separate metals and nonmetals from crushed particles of waste printed circuit boards. J. Electrost. 2007, 65, 233− 238. (5) Gallegos-Acevedo, P. M.; Espinoza-Cuadra, J.; Olivera-Ponce, J. M. Conventional flotation techniques to separate metallic and nonmetallic fractions from waste printed circuit boards with particles nonconventional size. J. Min. Sci. 2015, 50, 974−981. 18507


ACS Omega

Article

nano sheets as a water-tolerant solid acid catalyst. Chem. Commun. 2008, 42, 5363−5365. (26) Hegner, J.; Pereira, K. C.; DeBoef, B.; Lucht, B. L. Conversion of cellulose to glucose and levulinic acid via solid-supported acid catalysis. Tetrahedron Lett. 2010, 51, 2356−2358. (27) Zhao, J.; Jayakumar, A.; Lee, J.-M. Bifunctional Sulfonated MoO3−ZrO2 Binary Oxide Catalysts for the One-Step Synthesis of 2, 5-Diformylfuran from Fructose. ACS Sustainable Chem. Eng. 2018, 6, 2976−2982. (28) Wu, Y.; Fu, Z.; Yin, D.; Xu, Q.; Liu, F.; Lu, C.; Mao, L. Microwave-assisted hydrolysis of crystalline cellulose catalyzed by biomass char sulfonic acids. Green Chem. 2010, 12, 696−700. (29) Rehman, M. S. U.; Umer, M. A.; Rashid, N.; Kim, I.; Han, J.-I. Sono-assisted sulfuric acid process for economical recovery of fermentable sugars and mesoporous pure silica from rice straw. Ind. Crops Prod. 2013, 49, 705−711. (30) Singh, N.; Chakraborty, R.; Gupta, R. K. Mutton bone derived hydroxyapatite supported TiO2 nanoparticles for sustainable photocatalytic applications. J. Environ. Chem. Eng. 2018, 6, 459−467. (31) Misra, M.; Singh, N.; Gupta, R. K. Enhanced visible-light-driven photocatalytic activity of Au@ Ag core−shell bimetallic nanoparticles immobilized on electrospun TiO2 nanofibres for degradation of organic compounds. Catal. Sci. Technol. 2017, 7, 570−580. (32) Fan, H.; Li, G.; Yang, F.; Yang, L.; Zhang, S. Photodegradation of cellulose under UV light catalysed by TiO2. J. Chem. Technol. Biotechnol. 2011, 86, 1107−1112. (33) Radhakumari, M.; Ball, A.; Bhargava, S. K.; Satyavathi, B. Optimization of glucose formation in karanja biomass hydrolysis using Taguchi robust method. Bioresour. Technol. 2014, 166, 534−540. (34) Ismail, H. M. Characterization of the decomposition products of zirconium acetylacetonate: nitrogen adsorption and spectrothermal investigation. Powder Technology 1995, 85, 253−259. (35) Sahai, A.; Goswami, N.; Kaushik, S. D.; Tripathi, S. Cu/Cu 2 O/CuO nanoparticles: novel synthesis by exploding wire technique and extensive characterization. Appl. Surf. Sci. 2016, 390, 974−983. (36) Khojastehnezhad, A.; Moeinpou, F.; Vafaei, M. Molybdenum Oxide Supported on Silica (MoO3/SiO2): An Efficient and Reusable Catalyst for the Synthesis of 1, 8-dioxodecahydroacridines Under Solvent-free Conditions. J. Mex. Chem. Soc. 2017, 59, 29−35. (37) Hadi, P.; Gao, P.; Barford, J. P.; McKay, G. Novel application of the nonmetallic fraction of the recycled printed circuit boards as a toxic heavy metal adsorbent. J. Hazard. Mater. 2013, 252−253, 166− 170. (38) Dang, W.; Kubouchi, M.; Sembokuya, H.; Tsuda, K. Chemical recycling of glass fibre reinforced epoxy resin cured with amine using nitric acid. Polymer 2005, 46, 1905−1912. (39) Arnold, U.; Habicht, W.; Döring, M. Metal Doped Epoxy Resins−New Catalysts for the Epoxidation of Alkenes with High Long-Term Activities. Adv. Synth. Catal. 2006, 348, 142−150. (40) Khojastehnezhad, A.; Moeinpou, F.; Vafaei, M. Molybdenum Oxide Supported on Silica (MoO3/SiO2): An Efficient and Reusable Catalyst for the Synthesis of 1, 8-dioxodecahydroacridines Under Solvent-free Conditions. J. Mex. Chem. Soc. 2017, 59, 29−35. (41) Wang, C.-H.; Lee, C.-N.; Weng, H.-S. Effect of Acid Treatment on the Performance of the CuO− MoO3/Al2O3 Catalyst for the Destructive Oxidation of (CH3) 2S2. Ind. Eng. Chem. Res. 1998, 37, 1774−1780. (42) Umbarkar, S. B.; Biradar, A. V.; Mathew, S. M.; Shelke, S. B.; Malshe, K. M.; Patil, P. T.; Dagde, S. P.; Niphadkar, S. P.; Dongare, M. K. Vapor phase nitration of benzene using mesoporousMoO 3/ SiO 2 solid acid catalyst. Green Chem. 2006, 8, 488−493. (43) Liu, B.; France, L.; Wu, C.; Jiang, Z.; Kuznetsov, V. L.; AlMegren, H. A.; Al-Kinany, M.; Aldrees, S. A.; Xiao, T.; Edwards, P. P. Methanol-to-hydrocarbons conversion over MoO3/H-ZSM-5 catalysts prepared via lower temperature calcination: A route to tailor the distribution and evolution of promoter Mo species, and their corresponding catalytic properties. Chem. Sci. 2015, 6, 5152−5163.

(6) Veit, H. M.; Juchneski, N. C. d. F.; Scherer, J. Use of gravity separation in metals concentration from printed circuit board scraps. REM, Rev. Esc. Minas 2014, 67, 73−79. (7) Salbidegoitia, J. A.; Fuentes-Ordóñez, E. G.; González-Marcos, M. P.; González-Velasco, J. R.; Bhaskar, T.; Kamo, T. Steam gasification of printed circuit board from e-waste: effect of coexisting nickel to hydrogen production. Fuel Process. Technol. 2015, 133, 69− 74. (8) Shen, Y.; Chen, X.; Ge, X.; Chen, M. Thermochemical treatment of non-metallic residues from waste printed circuit board: Pyrolysis vs. combustion. J. Cleaner Prod. 2018, 176, 1045−1053. (9) Jianjun, H.; Jiabiao, S.; Yuedong, M.; Zhengzhi, L. DC arc plasma disposal of printed circuit board. Plasma Sci. Technol. 2004, 6, 2423. (10) Ma, L. Z.; Wang, H.; Qing, S.; Ma, L. Z. Recycling of the Epoxy Resin of the Waste Printed Circuit Boards Using Solvent Extraction. Adv. Mater. Res. 2012, 383−390, 3140−3144. (11) Jadhav, U.; Su, C.; Hocheng, H. Leaching of metals from large pieces of printed circuit boards using citric acid and hydrogen peroxide. Environ. Sci. Pollut. Res. 2016, 23, 24384−24392. (12) Wath, S. B.; Katariya, M. N.; Singh, S. K.; Kanade, G. S.; Vaidya, A. N. Separation of WPCBs by dissolution of brominated epoxy resins using DMSO and NMP: A comparative study. Chem. Eng. J. 2015, 280, 391−398. (13) Verma, H. R.; Singh, K. K.; Mankhand, T. R. Dissolution and separation of brominated epoxy resin of waste printed circuit boards by using di-methyl formamide. J. Cleaner Prod. 2016, 139, 586−596. (14) Zhu, P.; Chen, Y.; Wang, L. Y.; Qian, G. R.; Zhou, M.; Zhou, J. A novel approach to separation of waste printed circuit boards using dimethyl sulfoxide. Int. J. Environ. Sci. Technol. 2013, 10, 175−180. (15) Zhou, P.; Barford, J.; McKay, G. Electronic waste as a new precursor for adsorbent production. The SIJ Transactions on Industrial. Financial & Business Management (IFBM) 2013, 1, 126− 135. (16) Kan, Y.; Yue, Q.; Kong, J.; Gao, B.; Li, Q. The application of activated carbon produced from waste printed circuit boards (PCBs) by H3PO4 and steam activation for the removal of malachite green. Chem. Eng. J. 2015, 260, 541−549. (17) Zheng, Y.; Shen, Z.; Cai, C.; Ma, S.; Xing, Y. The reuse of nonmetals recycled from waste printed circuit boards as reinforcing fillers in the polypropylene composites. J. Hazard. Mater. 2009, 163, 600−606. (18) Mosihuzzaman, M.; Quddus, A.; Nahar, N.; Theander, O. Comparative Study of Carbohydrates in the Two Major Species of jute (Corchoruscapsularis and Corchorusolitorius). J. Sci. Food Agric. 1989, 48, 305−310. (19) Theander, P. K.; Roy, U.; Vora, V. C. Hydrolysis of wheat bran, rice bran and jute powder by immobilized enzymes from Macrophominaphaseolina. World J. Microbiol. Biotechnol. 1993, 9, 164−167. (20) Matsagar, B. M.; Hossain, S. H.; Islam, T.; Alamri, H. R.; Alothman, Z. A.; Yamauchi, Y.; Dhepe, P. L.; Wu, K. C.-W. Direct Production of Furfural in One-pot Fashion from Raw Biomass Using Brønsted Acidic Ionic Liquids. Sci. Rep. 2017, 7, 13508. (21) Harris, E. E.; Kline, A. A. Hydrolysis of wood cellulose with hydrochloric acid and sulfur dioxide and the decomposition of its hydrolytic products. J. Phys. Chem. A 1949, 53, 344−351. (22) Goswami, M.; Meena, S.; Navatha, S.; Rani, K. N. P.; Pandey, A.; Sukumaran, R. K.; Prasad, R. B. N.; Devi, B. L. A. P. Hydrolysis of biomass using a reusable solid carbon acid catalyst and fermentation of the catalytic hydrolysate to ethanol. Bioresour. Technol. 2015, 188, 99−102. (23) Guo, F.; Fang, Z.; Xu, C. C.; Smith, R. L., Jr. Solid acid mediated hydrolysis of biomass for producing biofuels. Prog. Energy Combust. Sci. 2012, 38, 672−690. (24) Shrotri, A.; Kobayashi, H.; Fukuoka, A. Cellulose Depolymerization over Heterogeneous Catalysts. Acc. Chem. Res. 2018, 51, 761−768. (25) Takagaki, A.; Tagusagawa, C.; Domen, K. Glucose production from saccharides using layered transition metal oxide and exfoliated 18508


ACS Omega

Article

(63) Mittal, M.; Sharma, M.; Pandey, O. P. UV−Visible light induced photocatalytic studies of Cu doped ZnO nanoparticles prepared by co-precipitation method. Sol. Energy 2014, 110, 386−397. (64) Miller, G. L. Use of Dinitrosalicylic Acid Reagent for Determination of Reducing Sugar. Anal. Chem. 1959, 31, 426−428.

(44) Mohamed, M. M. Fourier-transform infrared/photoacoustic study of pyridine adsorbed on silica supported copper-molybdenum catalysts. Spectrochim. Acta, Part A 1995, 51, 1−9. (45) Kataoka, T.; Dumesic, J. A. Acidity of unsupported and silicasupported vanadia, molybdena, and titania as studied by pyridine adsorption. J. Catal. 1988, 112, 66−79. (46) Skupiński, W.; Malesa, M. An infrared study on the MoO3/ SiO2 catalytic system employed in toluene nitration. Appl. Catal., A 2002, 236, 223−234. (47) El-Shobaky, G. A.; Fagal, G. A.; Petro, N.; Dessouki, A. M. Effects of gamma irradiation on surface and catalytic properties of Co3O4 supported on Al2O3. Int. J. Radiat. Appl. Instrum., Part C 1987, 29, 39−43. (48) Zhao, Y.; Wang, S.; Lin, H.; Chen, J.; Xu, H. Influence of a Lewis acid and a Brønsted acid on the conversion of microcrystalline cellulose into 5-hydroxymethylfurfural in a single-phase reaction system of water and 1, 2-dimethoxyethane. RSC Adv. 2018, 8, 7235− 7242. (49) de Oliveira, A. d. N.; Costa, L. R. d. S.; Pires, L. H. d. O.; do Nascimento, L. A. S.; Angélica, R. S.; da Costa, C. E. F.; Zamian, J. R.; Filho, G. N. d. R. Microwave-assisted preparation of a new esterification catalyst from wasted flint kaolin. Fuel 2013, 103, 626− 631. (50) El-Molla, S. A.; Hammed, M. N.; El-Shobaky, G. A. Catalytic conversion of isopropanol over NiO/MgO system doped with Li2O. Mater. Lett. 2004, 58, 1003−1011. (51) Zhao, J.; Jayakumar, A.; Lee, J.-M. Bifunctional Sulfonated MoO3−ZrO2 Binary Oxide Catalysts for the One-Step Synthesis of 2, 5-Diformylfuran from Fructose. ACS Sustainable Chem. Eng. 2018, 6, 2976−2982. (52) Liu, Y.; Bailey, P.; Noakes, T. C. Q.; Thompson, G. E.; Skeldon, P.; Alexander, M. R. Chemical environment of copper at the surface of a CuAl2 model alloy: XPS, MEIS and TEM analyses. Surf. Interface Anal. 2004, 36, 339−346. (53) Choudhury, B.; Dey, M.; Choudhury, A. Shallow and deep trap emission and luminescence quenching of TiO2 nanoparticles on Cu doping. Appl. Nanosci. 2013, 4, 499−506. (54) Filonov, A. B.; Tralle, I. E.; Dorozhkin, N. N.; Migas, D. B.; Shaposhnikov, V. L.; Petrov, G. V.; Anishchik, V. M.; Borisenko, V. E. Semiconducting properties of hexagonal chromium, molybdenum, and tungsten disilicides. Phys. Status Solidi B 1994, 186, 209−215. (55) Rinaldi, R.; Meine, N.; vom Stein, J.; Palkovits, R.; Schüth, F. Which Controls the Depolymerization of Cellulose in Ionic Liquids: The Solid Acid Catalyst or Cellulose? ChemSusChem 2010, 3, 266− 276. (56) Bauer, B.; Floyd, T. A. Monitoring of glucose in biological fluids by Fourier−transform infrared spectrometry with a cylindrical internal reflectance cell. Anal. Chim. Acta 1987, 197, 295−301. (57) Gremlich, H. U.; Infrared and Raman spectroscopy. In Ullmann’s Encyclopedia of Industrial Chemistry, Vol. B5,VCH: Weinheim, Switzerland, 1994; pp 429−469. (58) Ward, K. J.; Haaland, D. M.; Robinson, M. R.; Eaton, R. P. Post-Prandial Blood Glucose Determination by Quantitative MidInfrared Spectroscopy. Appl. Spectrosc. 1992, 46, 959−965. (59) Petibois, C.; Rigalleau, V.; Melin, A.; Perromat, A.; Cazorla, G.; Gin, H.; Deleris, G. Determination of glucose in dried serum samples by Fourier-transform infrared spectroscopy. Clin. Chem. 1999, 45, 1530−1535. (60) Llano, T.; Quijorna, N.; Andrés, A.; Coz, A. Sugar, acid and furfural quantification in a sulphite pulp mill: Feedstock, product and hydrolysate analysis by HPLC/RID. Biotechnol. Rep. 2017, 15, 75−83. (61) Duan, S.; Feng, X.; Cheng, L.; Peng, Y.; Zheng, K.; Liu, Z. Bio degumming technology of jute bast by Pectobacterium sp. AMB Express 2016, 6, 86. (62) Hemmann, F.; Agirrezabal-Telleria, I.; Jaeger, C.; Kemnitz, E. Quantification of acidic sites of nanoscopic hydroxylated magnesium fluorides by FTIR and 15N MAS NMR spectroscopy. RSC Adv. 2015, 5, 89659. 18509


Printed Circuit Board-Derived Glass Fiber-Epoxy Resin-Supported Mo

Recommend Documents