Multifunctional iron-biochar composites for the removal of potentially toxic elements, inherent cations, and hetero-chloride from hydraulic fracturing wastewater

作者：Yuqing Sun, Iris K.M. Yu, Daniel C.W. Tsang, Xinde Cao, Daohui Lin, Linling Wang, Nigel Graham, Daniel S. Alessi, Michael Komárek, Yong Sik Ok, Yujie Feng, Xiangdong Li · 发表于：Environment International · 年份：2019 · DOI：10.1016/j.envint.2019.01.047 · 被引用次数：490 · 研究领域：Environmental remediation with nanomaterials、Radioactive element chemistry and processing、Groundwater flow and contamination studies

This paper evaluates a novel sorbent for the removal of potentially toxic elements, inherent cations, and hetero-chloride from hydraulic fracturing wastewater (FWW). A series of iron-biochar (Fe-BC) composites with different Fe/BC impregnation mass ratios (0.5:1, 1:1, and 2:1) were prepared by mixing forestry wood waste-derived BC powder with an aqueous FeCl 3 solution and subsequently pyrolyzing them at 1000 °C in a N 2 -purged tubular furnace. The porosity, surface morphology, crystalline structure, and interfacial chemical behavior of the Fe-BC composites were characterized, revealing that Fe chelated with C O bonds as C O Fe moieties on the BC surface, which were subsequently reduced to a C C bond and nanoscale zerovalent Fe (nZVI) during pyrolysis. The performance of the Fe-BC composites was evaluated for simultaneous removal of potentially toxic elements (Cu(II), Cr(VI), Zn(II), and As(V)), inherent cations (K, Na, Ca, Mg, Ba, and Sr), hetero-chloride (1,1,2-trichlorethane (1,1,2-TCA)), and total organic carbon (TOC) from high-salinity (233 g L −1 total dissolved solids (TDS)) model FWW. By elucidating the removal mechanisms of different contaminants, we demonstrated that Fe-BC (1:1) had an optimal reducing/charge-transfer reactivity owing to the homogenous distribution of nZVI with the highest Fe 0 /Fe 2+ ratio. A lower Fe content in Fe-BC (0.5:1) resulted in a rapid exhaustion of Fe 0 , while a higher Fe content in Fe-BC (2:1) caused severe aggregation and oxidization...