小麦秸杆对水中Pb（2＋）和Cd（2＋）的吸附特性

以农业废弃物小麦秸杆为吸附材料,探讨了小麦秸杆对Pb2＋、Cd2＋的吸附特性,重点研究了吸附时间、离子浓度、溶液pH值等对小麦秸杆吸附Pb2＋、Cd2＋的影响.结果表明,溶液pH值对吸附的影响大,在pH 2.0～6.0范围内,吸附量随溶液初始pH值的升高而升高.小麦秸杆吸附Pb2＋、Cd2＋的速度快,吸附动力学过程可以...

Characteristics of Pb2+ and Cd2+ Sorption in Aqueous Solution by Wheat Straw

Wheat straw was used as biosorbent for lead and cadmium removal from aqueous solution. Especially, the effect of solution pH, contact time and ions concentration on the sorption process was intensively discussed. Result indicated that the metal removal was strongly dependent on solution pH and the sorption capacity increased with the increasing of solution pH in the pH range of 2.0-6.0. The sorption kinetic process fit well with the pseudo-second-order. Langmuir isotherm equation was used to evaluate the sorption capacity of the biomass. The q_max values for Pb²⁺ and Cd²⁺ were 0.15 mmol·g^-1 and 0.11 mmol·g^-1 respectively. After NaOH hydrolated, wheat straw showed higher sorption capacity both for Pb²⁺ and Cd²⁺, q_max values for Pb²⁺ and Cd²⁺ reached 0.31 and 0.22 mmol·g^-1 respectively. While the sorption capacity for Pb²⁺ and Cd²⁺ on esterified wheat straw decreased greatly. Fourier transform infrared spectroscopy (FTIR) analysis showed that carboxylic groups on the biomass play an important role in Pb²⁺ and Cd²⁺ sorption process.