Nadeem Muhammad, Mahmood A, Shahid S A, Shah S S, Khalid A M, McKay G
Department of Chemistry, University of Agriculture, Faisalabad 38040, Punjab, Pakistan.
J Hazard Mater. 2006 Dec 1;138(3):604-13. doi: 10.1016/j.jhazmat.2006.05.098. Epub 2006 Jun 6.
An indigenously prepared, steam activated and chemically modified carbon from husk and pods of Moringa oleifera (M. oleifera), an agricultural waste, was comparatively examined as an adsorbent for the removal of lead from aqueous solutions. Studies were conducted as a function of contact time, initial metal concentration, dose of adsorbent, agitation speed, particle size and pH. Maximum uptake capacities were found to be, 98.89, 96.58, 91.8, 88.63, 79.43% for cetyltrimethyl ammonium bromide (CTAB), phosphoric, sulfuric, hydrochloric acid treated and untreated carbon adsorbents, respectively. Bangham, pseudo-first- and second-order, intra-particle diffusion equations were implemented to express the sorption mechanism by utilized adsorbents. Adsorption rate of lead ions was found to be considerably faster for chemically modified adsorbents than unmodified. The results of adsorption were fitted to both the Langmuir and Freundlich models. Satisfactory agreement between the metal uptake capacities by the adsorbents at different time intervals was expressed by the correlation coefficient (R(2)). The Langmuir model represented the sorption process better than the Freundlich one, with R(2) values ranging from 0.994 to 0.998.
对一种由辣木（Moringa oleifera）的果壳和豆荚（农业废弃物）制备的、经蒸汽活化和化学改性的国产碳作为从水溶液中去除铅的吸附剂进行了比较研究。研究了接触时间、初始金属浓度、吸附剂剂量、搅拌速度、粒径和pH值等因素的影响。十六烷基三甲基溴化铵（CTAB）、磷酸、硫酸、盐酸处理过的碳吸附剂和未处理的碳吸附剂对铅的最大吸附容量分别为98.89%、96.58%、91.8%、88.63%、79.43%。采用班汉姆方程、准一级和准二级方程以及颗粒内扩散方程来描述所用吸附剂的吸附机理。发现化学改性吸附剂对铅离子的吸附速率比未改性的吸附剂快得多。吸附结果与朗缪尔模型和弗伦德利希模型均拟合良好。不同时间间隔下吸附剂对金属的吸附容量之间的良好一致性通过相关系数（R²）表示。朗缪尔模型比弗伦德利希模型能更好地描述吸附过程，R²值范围为0.994至0.998。
