Study On Selective Adsorption Of Heavy Metal Ni(?)and The Removal Of COD By Advanced Oxidation In The Actual Industrial Wastewater

With the rapid development of social industrial enterprises,water bodies are increasingly polluted by heavy metals and organic matter,especially when industrial waste water is discharged or disposed of properly,it will directly affect the self-purification of water bodies,leading to deterioration of water quality.Now people are increasingly aware of the serious harm caused by environmental water pollution,and thus the sewage to be treated and then discharged after the discharge has become a consensus.In this paper,the heavy metal Ni(II)pollution and the wasting of Ni(II)in industrial waste water,and the removal of COD(chemical oxygen demand)in wastewater are studied.The main contents of this study are summarized as follows:1.An unfamiliar functional monomer 2-(Allylmercapto)nicotinic acid(ANA),which contains both N and S groups that have a strong coordinating ability with nickel ions,is used for imprinting Ni(II).The obtained Ni(II)ion-imprinted polymer(Ni-IIP)shows a fast uptake ability for the removal of Ni(II),and its adsorption equilibrium time is less than 20 min.The maximum Ni(II)adsorption capacity of Ni-IIP is found to be 38.85 mg/g,at a temperature of 30°C and optimum pH of 6.Additionally,the adsorption is a spontaneous and endothermic process according to the obtained thermodynamic parameters.Besides,Ni-IIP shows excellent selectivity factors of 33.63,219.59,4.23,16.89 and 32.74 for Ni2+/Zn2+,Ni2+/Mg2+,Ni2+/Co2+,Ni2+/Cd2+and Ni2+/Cu2+,respectively.Moreover,the Ni-IIP used is stable because the adsorption capacity is 82.7% of the initial saturation binding capacity up to the 5th cycle.Most notably,the application of Ni-IIP in wastewater samples shows a high removal efficiency for Ni(II)of more than 93.4%.The results indicate that the Ni-IIP is an effective adsorption material,allowing for the selective removal of Ni(II)from aqueous solutions at high efficiency.2.We used the combined process of ferric-carbon Microelectrolysis and Fenton reagent to remove the COD in the high salinity and containing methanol pharmaceuti-cal wastewater(Jiangxi Dadi Industrial Co.,Ltd).To obtain the optimum experimental conditions,the effect of different factors on the removal efficiency of COD was studied.The First,the separation of salt and methanol from the original pharmaceutical wastewater is carried out by distillation under reduced pressure.Thisstep removes most of the COD from the original wastewater,resulting in a COD removal rate of 71.92%,which created favorable conditions for the subsequent treatment of the wastewater.The results of the optimized experiments show that both the ferric-carbon Micro-electrolysis and the Fenton reagent have a good effect on the removal of COD in the wastewater at pH = 3.The optimum reactant ratio of the Fenton reagent is nH2O2: nFe2+ = 3.The most reasonable reaction time for ferric-carbon Microelectrolysis and Fenton reagent reaction are 120 min and 75 min,respectively.In the end,the removal rate of COD in pharmaceutical wastewater was 73.02%,which was better than that of single process,and the COD removal rate increased to99.26% after the fifth cycle,so that the COD content in the wastewater has reached the the new pharmaceutical enterprises CODcr emission standard in "Integrated Wastewater Discharge Standard"(GB8978-1996).3.Further research the combination process of coagulation sedimentation +ferric-carbon Microelectrolysis-Fenton reagent,as the pretreatment of the target wastewater.Here we mainly to study the removal of COD in the following three kinds of wastewater(Jiangxi Jinyuan Lai Industrial Co.,Ltd),they are production wastewater(W1),wastewater produced by cleaning the equipment(W2)and the ground(W3),the optimum treatment conditions were determined.First,the removal rate of COD in the three kinds of industrial wastewater are 40.97%,78.90% and91.54% respectively by coagulation sedimentation with polyferric sulfate as coagulant.The optimum reaction pHs of ferric-carbon Microelectrolysis and Fenton reagent treatment in the three kinds of industrial wastewater are both in the range of 2-4.The optimum Fenton reagent ratio of W1,W2 and W3 are nH2O2: nFe2+ = 3,nH2O2: nFe2+ = 6and nH2O2: nFe2+ = 2,respectively.In addition,ferric-carbon Microelectrolysis and Fenton reagent both can get a better treatment effectt within the reaction time of 100 min.Finally,in each optimal operating conditions,W1,W2 and W3 were treated by the combination process,their COD removal rates reached 84.2%,96.34% and97.76% respectively after the first cycle.And after three times,twice and once of the combination process cycle,respectively,their COD content met the "Integrated Wastewater Discharge Standard"(GB8978-1996)first level discharge standard.