Article Cite This: Ind. Eng. Chem. Res. XXXX, XXX, XXX−XXX
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Synthesis, Characterization, Adsorption, and Isotopic Separation Studies of Pyrocatechol-Modified MCM-41 for Efficient Boron Removal Yuanzhi Chen, Jiafei Lyu, Yuming Wang, Tao Chen, Yue Tian, Peng Bai, and Xianghai Guo*
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Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin 300072, PR China S Supporting Information *
ABSTRACT: Selected by the conductive value change (Δ) caused by generated proton in the boric acid-polyol solutions, pyrocatechol (CL) and nitropyrocatechol (NCL) were grafted into the mesoporous MCM-41 material for boron removal and isotopic separation. The adsorption kinetics, isotherms and thermodynamics, effect of pH, adsorption mechanism, regeneration, and isotopic separation performance on the new materials were explored in this study. The adsorption equilibrium was reached within 10 h, with the maximum boron adsorption capacity reaching up to 1.799 mmol g−1 for CL-MCM-41 at pH 9 and 1.548 mmol g−1 for NCL-MCM-41 at pH 12, respectively. In addition, the boron isotopic separation factor was measured to be 1.158, which was significantly higher than that of commercial IRA 743. After four cycles of elution with acetic acid of low concentration, approximately 80% of the original adsorption capacity could be maintained, which also outperformed the commercial resins.
1. INTRODUCTION
efficiency boron removal methods from water with high boron contents. Membrane,9 adsorption,8 and hybrid process such as PEUF10 and AMF11 have been the main methods to remove boron from aqueous solutions. Adsorption has become one of the most effective methods for boron removal due to its low energy consumption and high technique maturity. Most boronspecific adsorbents were designed by incorporating functional polyols into the supports,12−15 which usually have large specific surface area and high stability. The most commercialized boron adsorbent, boron specific chelating resin, was synthesized by grafting N-methyl-D-glucamine into the resins.16−18 Besides, inorganic materials modified with polyol groups have been observed for boron removal by forming stable complexes with boron.19 Considering the crucial role of support on the performance of adsorbents, here we aimed to use mesoporous silica MCM-41 as the supporting carrier for the incorporation of functional polyols due to its remarkable properties including large pore volume and surface area, strong stability and regular porosity. In addition, a mass of silanol groups in MCM-41 can
Boron, a type of widespread element in the environment, acts as a necessary micronutrient for the growth of animals, plants, and human beings. Nevertheless, it will do harm to organisms if the boron concentration is a bit higher than needed, leading to a decline in production of vegetables and fruits.1 More importantly, excess boron disturbs the hormone balance and immune system of animals and humans.2 Therefore, the standards of boron content in agricultural water and drinking water are strict, but different in diverse regions. It is recommended that the content of boron in irrigation water should be
