| With the rapid development of electroplating industry, nickel plating technology has been more and more widely applied, as a national strategic reserve metal. The results lead to that electroplating nickel wastewater is also increasing. The production of nickel plating wastewater has become one of the sources of heavy metal pollution in the world. The wanton discharge of nickel plating wastewater leads to the enrichment of nickel in the human body through the biosphere cycle, thereby endangering the health of the human body. Therefore, the treatment of nickel plating wastewater and the effective recovery of nickel resources has aroused the attention of the society.In this paper, we adopt Ion exchange method, the static and dynamic adsorption exchange system of ion exchange is established. It is concluded that the optimal process conditions for the dynamic and continuous operation of electroplating nickel wastewater by ion exchange, by studying the optimization of ion exchange resin and the effect of various factors on the removal of nickel by ion exchange resin. And the nickel resources in the regeneration waste liquid are effectively recovered. The specific researches include:The effects of the adsorption and removal of nickel by different types of ion exchange resins were studied by batch experiments, and the best KP752 type and CH-90 type ion exchange resin were selected. We investigated the effects of initial concentration of solution, p H value and the amount of resin on the static adsorption of nickel ion by the ion exchange resins. The results show that: The removal rate of the nickel ion increases with the increasing of the initial concentration of the wastewater; When p H is in the 3~ 6 ranges, the adsorption removal effect of the resin is good; In a certain range, the increase of the amount of resin is beneficial to improve the removal rate of nickel ion. The resins before and after adsorption were characterized by scanning electron microscope, which found that the resins have excellent properties and large specific surface area, which is good for the adsorption of nickel ions.Adsorption thermodynamics and adsorption kinetics of KP752 type and CH-90 type ion exchange resin were studied based on the static adsorption experiments. Kinetic studies show that the Freundlich isotherm is more accurate to reflect the adsorption process of the two kinds of resins; the two stage kinetic equation is better for the adsorption kinetics data of two kinds of resins; the main control steps of the two kinds of resin adsorption processes are particle diffusion control. Thermodynamic study showed that two kinds of resin△G<0、△H>0、△S>0, the adsorption process belong to entropy driven spontaneous and endothermic reaction process.Dynamic adsorption and dynamic regeneration of resin were carried out by means of ion exchange dynamic continuous operation reaction device. We investigated the effects of influent flow rate, water hardness and COD concentration on the ion exchange process, and the effects of the regeneration rate, the concentration of the regeneration agent and the influent COD on the regeneration of the resin. The results showed that the influent flow rate was 10BV/h, the regeneration rate was 7BV/h, and the regeneration agent was 3% sulfuric acid solution; Wastewater hardness and influent COD can affect the adsorption effect of ion exchange resin on nickel ion; At the same time, influent COD affected the regeneration effect of resin, resulting in the decline of the recycling performance of resin. High purity nickel powder was prepared by using oxalic acid precipitation method to recover nickel from regenerated waste liquid. The recovery rate of nickel was 86.7%. |
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