An Experimental Research On Removal Of Heavy Metals In The Electroplating Wastewater By Natural Zeolite

Generally we take chemical method to treat electroplating wastewater, but there are some defects in chemical method including instability of effluent quality and running costs. For solving this problem, we spent about one year researching the ability of natural zeolite adsorbing heavy metals and did many dynamic and static experiments. During the dynamic experiments we analyze the effluent concentration and water-quality changing of chemical method and research the influence of some running conditions of natural zeolite adsorbing heavy metal; During the static experiments we particularly discuss the sorption capacity difference between the zeolite samples from Gong Yi ,HeNan province and JinHua ,ZheJiang province and between the two JinHua ZheJiang zeolites. Furthermore, we simulate the electroplating wastewater's influence factors on the spot and analyze these factors characteristics and reasons.The conclusions of dynamic experiments are as follows: 1) natural zeolites exhibit a relative stronger ability to adsorb Zn²⁺, and a very little adsorbing ability to Ni²⁺ in the presence of Zn²⁺; 2)the higher influent concentration is, the better natural zeolite sorption capacity to Zn²⁺ exhibits; 3)the sorption capacity of natural zeolite is relative to its regeneration effect and the NaCl concentration of 8% is relatively reasonable.The conclusions of static experiments are as follows: 1) zeolite material with high quality should be selected as adsorption agent as the adsorption capacity is strongly related to the material quality ; 2) a longer regeneration time produce a higher adsorption capacity, where a reasonable regeneration time was found to be 4h; 3) an optimum pH value which ensures the best adsorption performance is about 8 for Ni²⁺ and about 10 for Zn²⁺, respectively; 4) adsorption capacity turns to higher gradually with the rise in water temperature; 5) most organic matters in electroplating wastewater have less influence on adsorption capacity except the organic surfactant.