| Bentonite is a kind of clay mineral that is abundant in our country. It has unique samdwich structure and powerful adsorption ability. Modification of bentonite can improve its adsorption ability greatly and so makes it adsorb the contaminants such as heavy metal ions and organic substances in wastewater more effectively. Bentonite has lots of advantages in the treatment of wastewater, such as simple process, high efficiency and low cost. Above all the author refined the bentonite, determined its basic physicochemical properties, made modification experiment on it, and studied its structure and ingredient by means of XRD and XRF. Moreover, I systematically studied the factors that affect the adsorption of cupric ions from the wastewater on bentonite surface. The adsorption result of bentonite modified by various methods was compared and the best conditions for treatment were determined by experiments. Also I carried out desorption experiments by means of vitriol. In this article, I not only have conducted the research on the Daye non-ferrous metal company's wastewater containing heavy metals, but also have discussed the adsorption mechanism of cupric ions on the modified bentonite.The bentonite used in the experiments was the Ca- bentonite produced in Ezhou, Hubei. The raw bentonite was not good regarding the adsorption performance of cupric ions. In order to make the bentonite suitable for the treatment of the copper-containing wastewater, we carried out the bentonite modification research. The experiments resulted in four modified methods under the best preparation conditions. Na-bentonite: reaction time was 1h, pH=9, T=60℃, sodium reagent dosage was 8.75 g/L. Roasted bentonite: heating temperature was 450℃, heating time was 2h. Organic bentonite: reaction time was 1.5h, pH=8, modified reagent dosage was 50%, T=60℃. Microwave activated bentonite: middle fire, heating time was 8min.The adsorption experiments using the modified bentonite were carried out and the best adsorption conditions of cupric ions were given. Na-bentonite: solid-fluid ratio was 20g/L, T=30℃, adsorption time was 15min, pH=9, removing rate achieved 95.5%. Roasted bentonite: solid-fluid ratio was 33g/L, T=50℃, adsorption time was 30min, pH=8, removing rate achieved 89.21%. Organic bentonite: solid-fluid ratiowas 33g/L, T=40℃, adsorption time was 60min, pH=9, removing rate achieved 92.3%. Microwave activated bentonite: solid-fluid ratio was 20g/L, T=50℃, adsorption time was 30min, pH=9, removing rate achieved 92.3%.The desorption experiment results indicated that using vitriol as adsorbent, the copper in raw bentonite, microwave activated bentonite and Na-bentonite was not all easy to desorb under the acidic condition. The cupric ions may be a stable existence in the bentonite, safely deposit, and was not easy to cause secondary pollution.In this experiment purified bentonite was used to treat the wastewater from Daye non-ferrous metal company. Finally the best process conditions were indicated as follows: temperature wais 40℃, adsorption time was 15min, dosage was 67g/L. The orthogonal experiment results indicated that the dosage was the most important factor influencing the removing rate, followed by temperature and adsorption time.The paper used the advanced testing techniques such as XRF and XRD to carry out the characterization on the modified bentonite, and studied the adsorption mechanism of cupric ions on it. Regarding the isothermal experiments of roasted bentonite and Na-bentonite, it was indicated that these were two kinds of modified bentonites, whose adsorption behavior of cupric ions conformed to the Freundilich equation.The above findings have certain theoretical and practical significances for using the adsorption performance of bentonite to treat wastewater, especially the copper-containing wastewater. Simultaneously a new way to enhance the application value of bentonite in our country has been developed.
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