Production of activated biochar via a self-blowing strategy-supported sulfidated nanoscale zerovalent iron with enhanced reactivity and stability for Cr(VI) reduction
Production of activated biochar via a self-blowing strategy-supported sulfidated nanoscale zerovalent iron with enhanced reactivity and stability for Cr(VI) reduction
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DOI：
10.1016/j.jclepro.2021.128108
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发表时间：
2021-09
影响因子：
11.1
通讯作者：
Minxian Zhuang;Hui Wang;Lu Qi;Liqiang Cui;Guixiang Quan;Jinlong Yan
中科院分区：
文献类型：
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作者：
Minxian Zhuang;Hui Wang;Lu Qi;Liqiang Cui;Guixiang Quan;Jinlong Yan
将生物炭负载的纳米零价铁(NZVI)用于还原铬(VI)。然而，生物炭的低比表面积和nZVI的表面氧化限制了其对污染物的去除效率。本研究采用自吹法制备了活性生物炭，并将其作为硫化NZVI的载体(S-NZVI@ABC)。结果表明，S-NZVI@ABC的比表面积(414万m2g−1)显著高于商业生物炭负载的S NZVI(S NZVI@BC，62m2g−1)，且S-NZVI粒子分散均匀。与S-nZVI@BC相比，S-nZVI在ABC上的反应活性提高了23%。S-nZVI@ABC对铬(VI)的去除效率也远高于nZVI、nZVI@ABC。当S/铁比从0增加到0.5时，去除效率提高了近一倍。较高的投加量、较低的pH值和六价铬浓度有利于提高六价铬的去除效率。老化10d后，铬(VI)去除效率的保留率达到90%以上。在回收实验中，S-nZVI@abc也表现出了良好的可重用性。铬(VI)的去除过程属于吸热过程，符合Langmuir吸附等温式。S-NZVI@ABC对铬(VI)的去除涉及还原、沉淀和吸附等多种相互作用机制。
Biochar-supported nanoscale zero-valent iron (nZVI) has been unitized for the reduction of Cr(VI). However, the low specific surface area of biochar and the surface oxidation of nZVI limit its contaminant removal efficiency. In this study, activated biochar (ABC) was prepared through a self-blowing strategy and was used as a supporter for sulfidated nZVI (S-nZVI@ABC). The results revealed that S-nZVI@ABC had a significantly increased specific surface area (414 m2g−1) as compared to S-nZVI supported on commercial biochar (S-nZVI@BC, 62 m2g−1), and the S-nZVI particles were evenly dispersed. Compared with S-nZVI@BC, the reactivity S-nZVI on ABC increased by 23%. The removal efficiency of Cr(VI) by S-nZVI@ABC was also much higher than the content removed by nZVI, nZVI@ABC. The removal efficiency was nearly doubled when the S/Fe was increased from 0 to 0.5. Higher dosage, lower pH value and Cr(VI) concentration led to an increased Cr(VI) removal efficiency. The retention rate of Cr(VI) removal efficiency was higher than 90% after 10 days of aging. S-nZVI@ABC also showed good reusability in the recycling experiment. The removal process of Cr(VI) was classified as an endothermic process and fitted with the Langmuir adsorption isotherm. Multiple interaction mechanisms including reduction, precipitation, and adsorption were involved in the removal of Cr(VI) by S-nZVI@ABC.