摘要
以拜耳法赤泥为原料,通过微波煅烧-酸活化联合处理制备改性赤泥,重点考察改性赤泥吸附剂的制备条件及其加入量、废水p H值、反应时间对吸附去除废水中Cr（Ⅵ）效果的影响;采用比表面积仪（BET）和X-射线粉末衍射仪（XRD）对改性赤泥吸附剂进行表征,探讨了赤泥改性机理。结果表明：在微波煅烧-酸活化联合作用下,赤泥比表面积显著增大,其吸附除Cr（Ⅵ）的能力增强。微波功率为300 W、煅烧时间为20 min、盐酸浓度为3.0 mol/L、吸附剂粒径为120~180μm的改性赤泥吸附剂除Cr（Ⅵ）的能力最佳;在25℃,废水p H值为5.0,吸附反应时间为120 min,吸附剂加入量为12 g/L时,废水中Cr（Ⅵ）去除率达98.9%,溶液p H显著影响Cr（Ⅵ）去除效果。此外,吸附饱和的改性赤泥可通过0.2 mol/L Na OH溶液脱附,脱附率达到95.1%。
An effective adsorbent for hexavalent chromium removal from aqueous system was pre- pared by combining microwave calcination and acid activation using Bayer red mud （RM） as the starting material. The preparation conditions of modified red mud （MRM） was studied and adsorp- tion of hexavalent chromium MRM was investigated as a function of dosage, pH, and reaction time. MRM was characterized by specific surface area （BET） and X-Ray Powder Diffraction （XRD）. The results show that the specific surface area of RM is increased significantly by micro- wave calcination and subsequent acid activation and thus the adsorption ability for hexavalent chro- mium is improved greatly. The optimized conditions for preparing MRM are as follows： the power of microwave is 300 W, calcination time is 20 min, hydrochloric acid concentration is 3.0 mol/L, and particle size of MRM is 120 - 180μm. Hexavalent chromium removal efficiency from the wastewater with pH of 5.0 can reach 98.9% at 25 ℃ for adsorption time of 120 min when MRM dosage is 12 g/L. Moreover, solution pH has a great influence on adsorption efficiency of hexavalent chromium. Additionally, MRM can be desorbed by 0. 2 mol/L NaOH solution with desorption efficiency of 95.1%.
出处
《广西大学学报（自然科学版）》
CAS
北大核心
2015年第5期1323-1329,共7页
Journal of Guangxi University（Natural Science Edition）
基金
广西自然科学基金资助项目(2012GXNSFBA053130)
广西大学"大学生创新创业训练计划"资助项目(1201057)
关键词
赤泥
微波
酸活化
改性
含Cr(Ⅵ)废水
red mud
microwave
acid activation
modified
wastewater containing hexavalentchromium
