硫酸盐还原颗粒污泥对溶液中Cr(Ⅵ)去除特性及总Cr平衡吸附研究

利用小型EGSB反应器培养的硫酸盐还原颗粒污泥进行Cr(Ⅵ)去除实验,考察硫酸盐还原颗粒污泥对Cr(Ⅵ)的去除特性及对总Cr的平衡吸附并进行吸附等温式拟合.结果表明,颗粒污泥对Cr(Ⅵ)的去除是物理、化学及生物过程共同作用的结果,主要包括了还原及吸附作用.颗粒污泥对Cr(Ⅵ)的去除作用与环境因素、颗粒污泥的化学组成和结构的完整程度等密切相关.对Cr(Ⅵ)的去除速率随颗粒污泥投加量及Cr(Ⅵ)初始浓度的增加而提高;提高振荡速度和温度均可提高Cr(Ⅵ)的去除效率及对总Cr的吸附速率,但当振荡速度达到150r·min-1时或温度达到40℃时颗粒污泥会出现结构的离散并降低总Cr的平衡吸附量;pH值越低颗粒污泥对Cr(Ⅵ)的去除效率就越高,但颗粒污泥表面的硫化物在pH值为酸性时会转化成H2S气体逸出,并因此影响对总Cr的吸附效率.颗粒污泥对总Cr的最大吸附量为6.84mg·g-1,其对总Cr的吸附过程符合Langmuir吸附等温式.

Characterization of Cr (VI) removal and total Cr equilibrium adsorption by sulfate reducing granular sludge in stimulant wastewater

Sulfate reducing granular sludge (SRGS) cultivated in small scale EGSB reactor was used for Cr (VI) removing. Characterization of Cr (VI) removal and total Cr equilibrium adsorption was studied, and the adsorption isotherm was fitted. Results showed that removal of Cr (VI) was in connection with the structure and chemical composition of SRGS and several environmental factors. The Cr (VI) removal rate increased with the dosage of granular sludge; the increasing of oscillation speed and temperature could enhance Cr (VI) removal and total Cr adsorption, but while the oscillation speed reached 150 r x min(-1) or the temperature came to 40 degrees C, the physical structure of granular sludge would be affected and the granular sludge discrete, and total Cr equilibrium adsorption decreased; lower pH value caused higher Cr (VI) removal rate, however the sulfate on the surface of granular sludge was affected by lower pH value easily and would translate into H2S, then total Cr adsorption rate decreased. Cr (VI) removal would be influenced by physical, chemical and biological factors, and the process included reduction and adsorption mainly. The maximum adsorption of total Cr by granular sludge was 6.84 mg x g(-1), and the total Cr adsorbing process fitted in with Langmuir adsorption isotherm.