Subscriber access provided by UNIVERSITY OF TOLEDO LIBRARIES
Remediation and Control Technologies
Removal of arsenic from strongly acidic wastewater using phosphorus pentasulfide as precipitant: UV-light promoted sulfuration reaction and particle aggregation Xianjia Peng, Jingyi Chen, Linghao Kong, and Xingyun Hu Environ. Sci. Technol., Just Accepted Manuscript • Publication Date (Web): 26 Mar 2018 Downloaded from http://pubs.acs.org on March 26, 2018
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 32
Environmental Science & Technology
1
Removal of arsenic from strongly acidic wastewater using
2
phosphorus pentasulfide as precipitant: UV-light promoted
3
sulfuration reaction and particle aggregation
4 5
Xianjia Peng1,2,3, Jingyi Chen1,2,3, Linghao Kong*,1,2, Xingyun Hu1,2
6
1. National Engineering Laboratory for Industrial Wastewater Treatment, Research Center
7
for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
8
2. Beijing Key Laboratory of Industrial Wastewater Treatment and Resource Recovery,
9
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing
10
100085, China
11
3. University of Chinese Academy of Sciences, Beijing 100049, China
12 13
* Corresponding author:
14
Linghao Kong
15 16
Tel: +86-10-6284 9198
17
Fax: +86-10-6284 9198
18
E-mail:
[email protected] 19
1
ACS Paragon Plus Environment
Environmental Science & Technology
20
ABSTRACT
21
Strongly acidic wastewater (H2SO4) with a high arsenic concentration is produced by many
22
industries. The removal of arsenic by traditional sulfide (e.g. Na2S, FeS) from strongly
23
acidic wastewater introduces cations (Na+ and Fe2+) to the solution, which may prevent the
24
recycle of acid. In this study, a new sulfuration agent, phosphorus pentasulfide (P2S5) was
25
employed, and its feasibility in arsenic removal from strongly acidic wastewater was
26
investigated. In the dark, As(III) was efficiently removed, but the removal rate of As(V) was
27
rather slow, which was the crucial defect for this method. We found that this defect can be
28
efficiently overcome by UV irradiation through accelerating the formation and
29
transformation of an intermediate species, monothioarsenate (H3AsO3S) in the As(V)
30
removal process. In addition, the hydrolysis of P2S5 was enhanced under UV irradiation,
31
which resulted in the increase of the arsenic removal efficiencies. Besides, the aggregation
32
of the formed particles was also promoted. Different from FeS and Na2S, P2S5 introduces
33
H3PO4 instead of cations to the solution, which can facilitate the recycle and reuse of arsenic
34
and acid in strongly acidic wastewater.
35 36
2
ACS Paragon Plus Environment
Page 2 of 32
Page 3 of 32
Environmental Science & Technology
37 38
3
ACS Paragon Plus Environment
Environmental Science & Technology
39
Introduction
40
Large quantities of strongly acidic wastewater with high arsenic concentration is
41
produced by nonferrous metal smelting industry, mineral processing industry, and sulfuric
42
acid production industry, etc. For instance, in a typical sulfuric acid production process,
43
pyrite ores or sulfide concentrates are roasted in fluidized beds to generate
44
arsenic-containing SO2. The gases are cleaned and thus strongly acidic wastewater with high
45
concentration of arsenic is produced in this process.1
46
The removal of arsenic from strongly acidic wastewater remains difficult. Current
47
technologies available for arsenic removal from acidic water include adsorption,
48
co-precipitation, bio-removal, etc. Adsorbents such as TiO2,2 iron (hydro)oxide modified
49
zeolite 3 and co-precipitation reagents, such as Fe(III) 4-6 have been utilized for the treatment
50
of arsenic-containing acidic wastewater. However, a weak acidic or neutral condition is
51
required in these methods, which means that a neutralization process using Na2CO3, sodium
52
hydroxide, ammonia and other alkaline reagents is necessary before the treatment. In these
53
processes, however, acid is lost irreversibly and the acidic wastewater is transformed to
54
wastewater with high concentration of salt which may still pose a threat to the environment.
55
Bioprocesses have also been developed for arsenic-containing acidic wastewater treatment
56
and high removal efficiencies of arsenic have been obtained under weak acidic conditions.
57
7-12
58
applied under mildly acidic conditions (pH range of 2-6),7-12 because the microbial activity
59
can be strongly inhibited by strongly acidic conditions (pH
