【摘要】 目的研究加碳焙烧改性新方法制备改性膨润土(Modified Bentonite,MB)作为Cr(Ⅵ)吸附剂的条件,探讨MB对Cr(Ⅵ)吸附的影响因素及吸附机理,旨在研发一种无害且经济的修复Cr(Ⅵ)污染土壤和地下水的可渗透反应墙(PRB)的反应介质.方法以Al2(SO4)3为改性剂对辽宁黑山钙基膨润土进行加碳焙烧改性.结果通过试验确定最佳改性条件:改性剂Al2(SO4)3投加量为25%,加碳量为2%,焙烧温度为420℃,焙烧时间为2 h.在13.5℃,溶液pH为6.5,MB投加量为20 g/L,搅拌45 min的条件下试验,MB对质量浓度为1 mg/L的Cr(Ⅵ)去除率达到98.21%,处理后Cr(Ⅵ)质量浓度达到地下水水质Ⅲ类标准,且表现出固液分离容易、处理土无解吸等优点.结论将改性膨润土MB作为PRB反应介质应用于修复Cr(Ⅵ)污染的土壤和地下水是可行的.更多还原

【Abstract】 The preparation condition for the integrated modified bentonite(MB) as Cr(Ⅵ) adsorbent was studied.The influence factors and mechanism of adsorbing Cr(Ⅵ) were discussed,with aiming at researching and developing a kind of harmless and economic reaction medium of Permeate Reactive Barrier in-situ remediation technology.A new modifying method on Ca-bentonite of Liaoning Heishan by carbon-entraining has been presented with the modifier of Al2(SO4)3 by roasting.The best modified condition is that the modifier Al2(SO4)3 of 25g and carbon of 2g are added in bentonite of 100g,respectively,and roasting temperature of 420 ℃ and roasting time of 2 h selected.Using MB to treat the water polluted by Cr(Ⅵ),the removal rate of 98.21% are achieved with Cr(Ⅵ) concentration of 1 mg/L,the temperature of 13.5 ℃,pH value of 6.5,MB dosage of 20 g/L and reaction time of 45 min.The Cr(Ⅵ) concentration of treated water is less than the national groundwater quality Ⅲ standard.Simultaneously,the MB shows the advantage of no-desorption and easier liquid-solid separation.It is feasible with MB as the reaction medium of PRB to remedy the polluted soil and groundwater by the Cr(Ⅵ).更多还原