铜尾矿对水溶液中磷的吸附与解吸

Adsorption-desorption Characteristics of Dissolved Phosphorus on Surface of Copper Mine Tailings

为研究铜尾矿作为吸附剂对水溶液中磷的吸附与解吸,从铜陵尾矿库采取尾矿样本,以其作为吸附材料对KH2PO4配制的水溶液进行吸附,用比色法测定磷的平衡浓度,然后计算平衡吸附量和解吸量。结果表明,Langmuir和Freundlich等温吸附方程能够较好地描述铜尾矿对水溶液中磷的吸附过程;尾矿废弃物对水溶液中磷酸根的吸附量与尾矿样本中游离氧化铁、晶质氧化铁、有机络合铁含量以及烧失量呈极显著正相关,而与pH呈极显著负相关;各种植物群落下A层尾矿对磷的吸附量低于C层,尾矿对水溶液中磷的平均最大吸附量超过0.85 mg.g-1,铜官山老尾矿库白茅群落下硬盘层对水溶液中磷的平均最大吸附量达到8.66 mg.g-1,被铜尾矿吸附的磷的平均解吸率低于5%。

The research using ecological restoration method to resolve abundant cumulate mine tailings is becoming a hot spot,however,the bioavailable phosphorus utilized by vegetation in the mine tailings is relatively low.The adsorption and desorption characteristics of dissolved phosphorus on surface of copper mine tailings was studied on the view of phosphorous bioavailability.Furthermore the effect of mine tailings on the process of ecological restoration was explored.The copper mine tailings samples from Tongling tailings reservoir were used as adsorp-tion material to adsorb phosphorus from solution prepared with KH2PO4 concentrations.After washing the equilibrium solution twice with sat-urated NaCl solution to remove dissociative phosphorus and adding CaCl2 solution to proceed desorption experiment,the phosphorus concen-tration in equilibrium was determined by spectrophotometric method and the equilibrium adsorption capacity and desorption capacity were calculated.Both adsorption and desorption processes were shaken for 1 hour,maintained the equilibrium for 24 hours and then centrifuged.The adsorption isotherm experiment,using a series of KH2PO4 concentrations with pH 7,was conducted to vibrate for 3 hours under constant temperature（25 ℃）.The result indicated that the adsorption isotherm data were preferably described by both the Langmuir and Freundlich isotherm models.The adsorption capacity with the free ferric oxide,crystalloid ferric oxide,chelated ferric oxide and loss in ignition of copper mine tailings was highly significant positive relation,but the highly significant negative relation with pH.The adsorption capacity of A layers for every plant community was lower than that of C layers.The average maximum adsorption capacity of copper mine tailings on phosphorus was above 0.85 mg.g-1,and the average maximum adsorption capacity of oxidation layers under cogon community of Tongguanshan tailings reservoir was 8.66 mg.g-1.The average desorption rate of adsorbed phosphorus was less than 5%.