Gong Renmin, Zhong Keding, Hu Yun, Chen Jian, Zhu Guoping
College of Life Science, Anhui Normal University, Wuhu 241000, PR China.
J Environ Manage. 2008 Sep;88(4):875-80. doi: 10.1016/j.jenvman.2007.04.004. Epub 2007 Jun 8.
In this paper, rice straw was esterified thermochemically with citric acid (CA) to produce potentially biodegradable cationic sorbent. The modified rice straw (MRS) and crude rice straw (CRS) were evaluated for their methylene blue (MB) removal capacity from aqueous solution. The effects of various experimental parameters (e.g., initial pH, sorbent dose, dye concentration, ion strength, and contact time) were examined. The ratio of MB sorbed on CRS increased as the initial pH was increased from pH 2 to 10. For MRS, the MB removal ratio came up to the maximum value beyond pH 3. The 1.5 g/l or up of MRS could almost completely remove the dye from 250 mg/l of MB solution. The ratio of MB sorbed kept above 98% over a range from 50 to 450 mg/l of MB concentration when 2.0 g/l of MRS was used. Increase in ion strength of solution induced decline of MB sorption. The isothermal data fitted the Langmuir model. The sorption processes followed the pseudo-first-order rate kinetics. The intraparticle diffusion rate constant (k(id)) was greatly increased due to modification.
在本文中，稻草与柠檬酸（CA）进行热化学酯化反应以制备具有潜在生物降解性的阳离子吸附剂。对改性稻草（MRS）和粗稻草（CRS）从水溶液中去除亚甲基蓝（MB）的能力进行了评估。考察了各种实验参数（如初始pH值、吸附剂剂量、染料浓度、离子强度和接触时间）的影响。随着初始pH值从2增加到10，CRS上吸附的MB比例增加。对于MRS，在pH值超过3时，MB去除率达到最大值。1.5 g/l及以上的MRS几乎可以完全从250 mg/l的MB溶液中去除染料。当使用2.0 g/l的MRS时，在50至450 mg/l的MB浓度范围内，MB吸附比例保持在98%以上。溶液离子强度的增加导致MB吸附量下降。等温数据符合朗缪尔模型。吸附过程遵循准一级速率动力学。由于改性，颗粒内扩散速率常数（k(id)）大大增加。
