The Static Adsorption For Pb(Ⅱ) And Cd(Ⅱ) In Water By The Material Of In-situ Capping

Xiangjiang River is the mother river of Hunan Province,because of a lot of heavyindustries in Zhuzhou, the river of Zhuzhou was seriously polluted which alsoeffected the downstream Changsha and Xiangtan. Comprehensive treatment andpollution prevention of sediment,a ubiquitous and significant environmental issue inthe world,is one of the biggest problems in urban river treatment．A variety of toxicand hazardous pollutants in the sediment will release to aquatic environment throughexchange,which is the major source of polluting overlying water．It has had much treatment technology for polluted sediment in overse．To use theforeign technology for reference and explore a suitable method for sediment pollutioncontrol in china is a good idea for us now．The key of this paper is try to make use ofcoral and acrylic resin as the major component of capping material，aim at the heavymetals in the sediment and combine with the strong adsorption capacity and specialcrystal structure of fluoroapatite and bentonite．After having a basic understandingabout sediment property in Xiawan Habor of Xiangjiang River, try to discuss themechanism ofheavy metals immobilized by novel capping material．Firstly,this paper studies the heavy metal content in the sediments which arefrom the Xiawan Habor of Xiangjiang River. Then testing the adsorption properties ofa variety of adsorbents.Choosing the bset adsorbents to make the in-situ cappingmaterials. This kind of material was applied to immobilizing the heavy metal ions insitu in sediments and simultaneously adsorbing Pb²⁺and Cd²⁺in water body. Theadsorptive property of this cap sealing materials was analyzed through fouriertransform infrared spectroscopy （FTIR）, scanning electron microscopy （SEM） andflame atomic absorption spectro-phototometer （FAAS）. The effect of pH and sorbentdosage on the absorption efficacy of above cap sealing materials was investigated.Results indicated：（1）The sediments of Xiawan Habor of Xiangjiang River are weakly alkaline, andthe pH is higher than8;（2）The content of Zn, Cu, Pb, Cd in the sediment are all much higher than thebackground value of soil. It also higher than other domestic maior rivers.（3）In the nine materials of the meth cellulose, acetate cellulose, amicrocrystalline, cellulose, diatomaceous earth, bentonite, chitin, a powdery chitin, coral as well as acrylate, resin, and the, etc.,the absorbent of acrylic resin, coral andchitin for Pb（II） and Cd（II） are best.After comprehensive comparising, choosing theacrylic resin and coral to make the in-situ capping material.（4）It was shown that at pH5.0, the absorbance of Cd²⁺ and Pb²⁺ peaks to434.67mg/g and524.27mg/g, respectively. The adsorbent capacity increased with theincrease of the initial concentration at the constant pH and adsorbent dosage.（5）The analysis results of FTIR and SCM indicated that this cap sealing materialshad high adsorptive property.