Study On Cu～(2+) Removal From Wastewater By DTPA-Modified Bentonite

At present, the study on application of modified bentonite in wastewater treatment focus mostly on the adsorption of organic pollutants on organobentonite. But little study is done about the adsorption of inorganic pollutants and especially hazardous heavy metal. The study on adsorption of Cu²⁺ from wastewater by modified bentonite was investigated in this thesis.Adsorbents used in these experiments of the paper are a kind of modified bentonite, which are synthesized using organic chelator DTPA and natural bentonite as raw materials. Using single factor experiment method and choosing simulation contamination water samples as research objects, we have investigated and drawn conclusions that the optimum experimental conditions of synthesizing the modified bentonite, its adsorption isothermal equation, the main factors affecting its adsorption performance and its application in electroplating wastewater treatment .The experimental results show that: the optimum experimental conditions of synthesizing the modified bentonite which can better adsorb Cu²⁺ are as follows: the optimum ratio (mass ratio) of modifier to Na soil is one to three; the optimum temperature of water bath is 60℃; the optimum organic time is 1.5h; the optimum pH is 8.0. The process that the modified bentonite adsorbs Cu²⁺ conform to Langmuir and Freundlich adsorption isothermal equation; this adsorption reaction is exothermic reaction. The factors which affect the size of adsorption performance which the modified bentonite adsorbs Cu²⁺ are as follows: the quantity of the modified bentonite to be used; pH; the adsorption time of constant temperature oscillation and the water bath temperature of constant temperature oscillation. The experiment results show that: the dosage of the modified bentonite to be used is 60g/L; pH is 5.0⁷.0 ; the adsorption time of constant temperature oscillation is 30 minute and the water bath temperature of constant temperature oscillation is 20℃.On the above experimental conditions, the adsorption removal rate of the modified bentonite to Cu²⁺ reaches above 90% .