Preparation Of PVA-based Polysilicon Hybrid Cation Membrane And Its Use In The Treatment Of Nickel-containing Wastewater

Polyvinyl alcohol?PVA?was used as membrane substrate material,organic-inorganic PVA-hybrid cation exchange membranes have been prepared through sol-gel reaction of the sulfonic silane and the multisilicon copolymers respectively.And they have been applied to the treatment of nickel-containing wastewater by electrolysis.The results were compared with those of the traditional electrolytic method to test the feasibility of application through hybrid cationic membrane electrolysis in heavy metal wastewater and obtain the optimal combination of process parameters.The main processes of hybrid membranes and best process parameters are as following:?1?The sulfonic acid silanes have been prepared through 2-ethyl sulfonic acid sodium and 3-aminopropyl trimethoxysilane.The effect of the content of silanes to the hybrid membrane was investigated through water content,ion exchange capacity,thermal stability and water swelling resistance.With increasing silanes content,the cation exchange capacity of hybrid membranes increased steadily,the water content and swelling degree of the hybrid membranes have improved and the thermal stability was enhanced.?2?The multisilicon copolymers poly?SSS-co-?-MPS?have been prepared through the organic monomer sodium styrene sulfonate?SSS?and?-?methacryloxypropyl?trimethoxy silane.The effect of the content of SSS to the copolymer poly?SSS-co-?-MPS?was investigated through water content,ion exchange capacity,thermal stability and water swelling resistance.With increasing SSS content,the water content?W_R?gradually increased,the cation exchange capacity have improved,the thermal stability decreased slightly.The swelling degree of membranes in 40oC water increased from 79.0%to 118.7%.The experimental results showed that the hybrid cation exchange membranes have excellent water swelling resistance.?3?The sulfate solution of nickel was used as simulative nickel wastewater,the research on retrieving heavy metal from wastewater was carried out by using self-made hybrid cation membrane.Effects of the temperature,the pH value of cathode solution,the polar distance of electrodes,the current density,membrane types and the Ni²⁺content of cathode solution on electrolysis process were investigated by using single factor alternate method respectively.Electrolytic experiments were carried out with graphite plate as anode and foamed nickel plate as cathode and the cathode solution was 10g/L nickel sulfate solution.The result was used to compare to the traditional electrolysis.The optimal process parameters of the membrane electrolysis experiments are as following:When the temperature is 35oC,the polar distance of electrodes is 25mm,the pH value of cathode solution is 4.5,the current density is250A/m² and electrolytic time is 20h,then the precipitation rate of Ni²⁺can achieve 87.7%,the average current efficiency can achieve 72.2%,and its electrolysis efficiency is much better than that of traditional electrolysis.As a result,the treatment of nickel wastewater by using the hybrid membrane electrolytic method is a feasible treatment process.And it has important theory research value and application value on the recycling and reusing of heavy metal wastewater.