Adsorption-desorption Characteristics of Dissolved Phosphorus on Surface of Copper Mine Tailings
ZHANG Hui,CHEN Zheng,GAO Yi,SUN Qing-ye(Anhui Key Laboratory of Ecological Engineering and Biotechnology,School of Life Science,Anhui University,Hefei 230039,China)
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%.
【Fund】： 国家高技术研究发展计划(863)资助项目(2006AA06Z359);; 安徽省自然科学基金资助项目(070415208)
【CateGory Index】： X753
【CateGory Index】： X753