| Coal chemical wastewater has the characteristics of large amount of water and complex quality,which is difficult to be treated in industry.Phenolic substances as a kind of high concentration organic matter in coal chemical wastewater have high recycling value.At present,the solvent extraction process is widely used for the separation of phenolic organic compounds in coal chemical wastewater at home and abroad,but this process has disadvantages such as difficult operation,easy to cause secondary pollution and high cost,which greatly restricts the development of coal chemical industry.Therefore,this article adopted the resin adsorption process phenolic separation recycling organic matter in waste water of coal chemical industry,to study the process of resin under the best conditions of adsorption and regeneration of separation device on this basis,we design a simple,low cost of phenol organic efficient separation methods,research train of thought for chemical waste water recycling and disposal.The main results are as follows:(1)The actual production wastewater of a coal chemical plant in Shaanxi Province was taken as the adsorption object,and the water quality was analyzed.The results showed that the concentration of phenolic substances in the wastewater to be treated was 5,800-6,300 mg/L.Gas chromatography was used to analyze phenolic organic compounds,and it was found that the raw water contained a variety of phenols,among which the concentration of phenol was 1982.94 mg/L.The proportion was the highest at30.3%.At the same time,it also contains other kinds of pollutants,including oil concentration of 1500-1800 mg/L,ammonia nitrogen concentration of 5500-6000 mg/L,COD concentration of 38000-40000 mg/L.(2)XDA-1G macroporous resin was used as adsorption material to study its optimal adsorption conditions.The results showed that when pH=6.0 and adsorption temperature was 35℃,the volume ratio of resin to wastewater to be treated was 1: 8.After 2.0 h of adsorption,the concentration of volatile phenol in coal chemical wastewater decreased from 5921.09 mg/L to 939.08 mg/L,at this time,the removal rate is about 84.14%.According to the orthogonal optimization test,the order of influence of each factor in resin adsorption process is: resin dosage > adsorption temperature >adsorption time > pH value of water sample.The adsorption kinetics study showed that the adsorption process was mainly controlled by the diffusion step,and the adsorption process was controlled by both membrane diffusion and intra-particle diffusion.The adsorption isotherm model shows that the adsorption process is monolayer adsorption.The results of adsorption thermodynamics showed that the adsorption process of XDA-1G resin for phenols in coal chemical wastewater was exothermic.(3)The regeneration conditions of XDA-1G macroporous resin were studied.99%methanol,HCl,Na Cl and Na OH were used as regenerators respectively,and the adsorption saturated resin was recycled under different conditions.The results showed that when the regenerator was 99% methanol,the regeneration temperature was 45℃,the volume of regenerator was 2.5 times,After 60 min of regeneration,the regeneration rate of resin reached 91.15%.At the same time,a cleaning method was established,and the regeneration rate reached 95.29% after cleaning.Cyclic adsorption and regeneration experiments show that the resin adsorption stability is good,and the removal rate of the first ten rounds is above 70%.BET,SEM and FTIR analysis showed that the resin had good adsorption effect on phenolic substances and the structure changed before and after regeneration.(4)The field test of the resin adsorption separation and recovery method for high concentration phenolic organic compounds in coal chemical wastewater showed that the phenolic organic compounds content in coal chemical wastewater was reduced from6143.41 mg/L to 1109.51 mg/L after dynamic treatment by resin adsorption process,and the removal rate reached 81.94%;In the first methanol regeneration,the regeneration rate was 95.21%.The system has good stability during the cycle treatment,and the removal rate reaches 72.36% after ten cycles.The effluent effect of field treatment is slightly lower than that of pilot test,which is mainly related to the complex quality of raw water and higher temperature.At the same time,this method can remove other common pollutants in wastewater to a certain extent,and the removal rates of oil,ammonia nitrogen,COD and UV254 in raw water are 51.89%,46.73%,77.59% and90.85%,respectively.It can also remove all kinds of heavy metals and organic matter to a certain extent. |
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