TY - JOUR
T1 - Removal of chlorinated organic solvents from hydraulic fracturing wastewater by bare and entrapped nanoscale zero-valent iron
AU - Lei, Cheng
AU - Sun, Yuqing
AU - Khan, Eakalak
AU - Chen, Season S.
AU - Tsang, Daniel C.W.
AU - Graham, Nigel J.D.
AU - Ok, Yong Sik
AU - Yang, Xin
AU - Lin, Daohui
AU - Feng, Yujie
AU - Li, Xiang Dong
N1 - Funding Information:
The authors appreciate the financial support from the National Natural Science Foundation of China ( 21407121 , 21525728 ), National Key Research and Development Program of China ( 2017YFA0207003 ), Hong Kong Research Grants Council (PolyU 15222115 and 15223517 ), and State Key Laboratory of Urban Water Resource and Environment of Harbin Institute of Technology ( HCK201309 ) for this study.
Funding Information:
The authors appreciate the financial support from the National Natural Science Foundation of China (21407121, 21525728), National Key Research and Development Program of China (2017YFA0207003), Hong Kong Research Grants Council (PolyU 15222115 and 15223517), and State Key Laboratory of Urban Water Resource and Environment of Harbin Institute of Technology (HCK201309) for this study.
Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2018/4
Y1 - 2018/4
N2 - With the increasing application of hydraulic fracturing, it is urgent to develop an effective and economically feasible method to treat the large volumes of fracturing wastewater. In this study, bare and entrapped nanoscale zero-valent iron (nZVI) were introduced for the removal of carbon tetrachloride (CT) and 1,1,2-trichloroethane (TCA) in model high-salinity fracturing wastewater. With increasing ionic strength (I) from Day-1 (I = 0.35 M) to Day-90 (I = 4.10 M) wastewaters, bare nZVI presented significantly lower removal efficiency of CT (from 53.5% to 38.7%) and 1,1,2-TCA (from 71.1% to 21.7%) and underwent more serious Fe dissolution from 1.31 ± 1.19% in Day-1 to 5.79 ± 0.32% in Day-90 wastewater. Particle aggregation induced by high ionic strength was primarily responsible for the lowered performance of nZVI due to less available reactive sites on nZVI surface. The immobilization of nZVI in alginate with/without polyvinyl alcohol provided resistance to particle aggregation and contributed to the superior performance of entrapped nZVI in Day-90 wastewater for 1,1,2-TCA removal (62.6–72.3%), which also mitigated Fe dissolution (4.00–4.69%). Both adsorption (by polymer matrix) and reduction (by immobilized nZVI) were involved in the 1,1,2-TCA removal by entrapped nZVI. However, after 1-month immersion in synthetic fracturing wastewater, a marked drop in the reactivity of entrapped nZVI for 1,1,2-TCA removal from Day-90 wastewater was observed with significant release of Na and total organic carbon. In summary, bare nZVI was sensitive to the nature of the fracturing wastewater, while the use of environmentally benign entrapped nZVI was more promising for wastewater treatment.
AB - With the increasing application of hydraulic fracturing, it is urgent to develop an effective and economically feasible method to treat the large volumes of fracturing wastewater. In this study, bare and entrapped nanoscale zero-valent iron (nZVI) were introduced for the removal of carbon tetrachloride (CT) and 1,1,2-trichloroethane (TCA) in model high-salinity fracturing wastewater. With increasing ionic strength (I) from Day-1 (I = 0.35 M) to Day-90 (I = 4.10 M) wastewaters, bare nZVI presented significantly lower removal efficiency of CT (from 53.5% to 38.7%) and 1,1,2-TCA (from 71.1% to 21.7%) and underwent more serious Fe dissolution from 1.31 ± 1.19% in Day-1 to 5.79 ± 0.32% in Day-90 wastewater. Particle aggregation induced by high ionic strength was primarily responsible for the lowered performance of nZVI due to less available reactive sites on nZVI surface. The immobilization of nZVI in alginate with/without polyvinyl alcohol provided resistance to particle aggregation and contributed to the superior performance of entrapped nZVI in Day-90 wastewater for 1,1,2-TCA removal (62.6–72.3%), which also mitigated Fe dissolution (4.00–4.69%). Both adsorption (by polymer matrix) and reduction (by immobilized nZVI) were involved in the 1,1,2-TCA removal by entrapped nZVI. However, after 1-month immersion in synthetic fracturing wastewater, a marked drop in the reactivity of entrapped nZVI for 1,1,2-TCA removal from Day-90 wastewater was observed with significant release of Na and total organic carbon. In summary, bare nZVI was sensitive to the nature of the fracturing wastewater, while the use of environmentally benign entrapped nZVI was more promising for wastewater treatment.
KW - 1,1,2-trichloroethane
KW - Alginate entrapment
KW - Carbon tetrachloride
KW - Fracturing wastewater treatment
KW - Iron dissolution
KW - nZVI
UR - http://www.scopus.com/inward/record.url?scp=85039755693&partnerID=8YFLogxK
U2 - 10.1016/j.chemosphere.2017.12.151
DO - 10.1016/j.chemosphere.2017.12.151
M3 - Article
C2 - 29289850
AN - SCOPUS:85039755693
SN - 0045-6535
VL - 196
SP - 9
EP - 17
JO - Chemosphere
JF - Chemosphere
ER -
