石棉尾矿酸浸渣对铬离子的吸附性能

Adsorption of Chromium Ion by Acid Leaching Residue of Asbestos Tailing

采用煅烧方法对石棉尾矿酸浸渣进行预处理,通过比表面积测定仪对煅烧前后的酸浸渣进行了表征,研究了煅烧后的石棉尾矿酸浸渣对溶液中Cr3+的吸附性能,并对吸附机理进行了探讨.实验结果表明,酸浸渣的比表面积随煅烧温度的提高而增加,600℃时达最大值379.33m2/g,此后随煅烧温度升高而下降;一定范围内,增加酸浸渣用量、延长吸附作用时间、升高吸附温度、提高pH值均可改善对Cr3+的吸附去除效果,其中pH的影响最大.酸浸渣对Cr3+的等温吸附符合Langmuir方程.由于酸浸渣表面ζ电位为负,酸浸渣对Cr6+的吸附远低于对Cr3+的吸附.基于EDX能谱及FT-IR光谱分析结果,确定酸浸渣对Cr3+的吸附主要为离子交换吸附和表面配位作用.

The acid leaching residue of asbestos tailing was pretreated by calcination. The uncalcined and calcined acid leaching residue samples were characterized by BET. Then the adsorption capability of calcined acid leaching residue of asbestos tailing to Cr^3＋ was studied. The adsorption mechanism of acid leaching residue was discussed. The results showed that the specific surface area of acid leaching residue increased with the calcination temperature and had a maximum value of 379.33 m^2/g at 600 ℃, after which the specific surface of acid leaching residue decreased with the calcination temperature. In some extent, the removal effect of Cr^3＋ was improved with increasing quantity of adsorbent, adsorption time, adsorption temperature and pH value of solution, pH value was the most influential factor. Analysis of experimental data showed that the model of isothermal adsorption accorded with Langmuir equation. Because the potential of acid leaching residue was negative in charge, the adsorption ability of acid leaching residue of asbestos tailing to Cr^6＋ was lower than that to Cr^3＋. Based on the analysis of EDX and FT-IR spectra, the adsorption mechanism of acid leaching residue to Cr^3＋ could be explained by both fimctions of ion exchange and surfacial coordination.