摘要
吸附法是一种去除水体中Cr(Ⅵ)的有效方法,但对废吸附剂的处置仍是一个非常棘手的问题。本研究通过简单水热-煅烧法制备了镁铝双金属氧化物吸附材料(MgAlO),研究了该材料对水体中Cr(Ⅵ)的吸附效果并评估了含Cr(Ⅵ)废吸附剂(Cr-MgAlO)对有机染料的去除性能。吸附实验结果表明,当材料投加量为1.0 g/L、初始pH=5.5时,MgAlO对Cr(Ⅵ)的最大吸附量达到95.2 mg/g。拟合结果表明,MgAlO对Cr(Ⅵ)的吸附行为符合假二级吸附动力学模型,说明吸附过程以化学吸附为主。材料的表征结果表明,吸附结束后MgAlO恢复了水滑石结构且层间存在CrO_(4)^(2-),高温能够加快MgAlO恢复水滑石结构。此外,含Cr(Ⅵ)的废吸附剂(Cr-MgAlO)对甲基橙(MO)的去除率达到75.6%,循环使用5次后去除率未见明显下降。本研究合成的MgAlO在处理Cr(Ⅵ)废水方面有潜在应用前景,为含Cr(Ⅵ)废吸附剂的处置和资源化利用提供了新思路。
Adsorption is considered an effective strategy for removing Cr(VI)from wastewater,but disposal of spent adsorbents is still a thorny problem.This work aims to develop an efficient adsorbent for Cr(VI)removal and recycling spent adsorbent as catalyst for the removal of organic dyes.In this study,MgAl-mixed oxides adsorbents(MgAlO)were synthesized via hydrothermal and calcination steps to effectively adsorb Cr(VI)from wastewater.The influence of initial pH and temperature on the adsorption performance of MgAlO was investigated.The maximum adsorption capacity for Cr(VI)was 95.2 mg/g at a MgAlO dosage of 1.0 g/L and a pH value of 5.5.The combination of XRD,FT-IR,and UV-vis DRS analyses revealed that CrO_(4)^(2-)anions were intercalated into the interlayer spaces of layered double hydroxides,and high temperatures can accelerate the reconstruction of MgAlO.The adsorption of Cr(VI)by MgAlO followed the pseudo-second-order kinetic model,which included intra-particle diffusion,film diffusion,and chemical reaction.Furthermore,the resulting spent adsorbent(Cr-MgAlO)after adsorption was reused as a catalyst for methyl orange(MO)removal after adsorption(75.6%removal rate)and showed no significant decrease in removal rate after 5 cycles.The results of this study provide insights into the reuse of spent Cr(VI)adsorbent for environmental catalytic applications,which are of great importance for the disposal of waste adsorbent.
作者
陈超荣
谢振宇
陈琪
彭蔚
王高锋
杨博文
葛飞
CHEN Chao-rong;XIE Zhen-yu;CHEN Qi;PENG Wei;WANG Gao-feng;YANG Bo-wen;GE Fei(Department of Environment,College of Environment and Resources,Xiangtan University,Xiangtan 411105,China;Key Laboratory of Environmental and Ecological Health of Hunan Province,Xiangtan 411105,China;Department of Physical and Chemical Examination,Xiangtan Center for Disease Control and Prevention,Xiangtan 411105,China;Guangdong Provincial Key Laboratory of Mineral Physics and Materials,Guangzhou 510640,China)
基金
Project(2023JJ40623)supported by the Hunan Provincial Natural Science Foundation,China
Project(2023B1212060048)supported by Science and Technology Planning Project of Guangdong Province,China
Project(22QDZ50)supported by Research Foundation for Ph D of Xiangtan University,China
Project(23B0153)supported by Excellent Youth Funding of Hunan Provincial Education Department,China
Project supported by the Aid Program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province,China。
