| The components of wastewater which flow into urban sewage treatment plants increasingly present the trend of industrial+municipal features.Thereinto,the large proportion of textile printing and dyeing wastewater and its impact on the treatment efficiencies of urban sewage plants can not be ignored.As one of the traditional advantage industries of our country,the printing and dyeing sewage is of great quantity,high colority and poor biochemical purification ability.The conventional processes are often unable to cope with it,combined with environmental protection requirement deepening,so ti is imminent to explore a high efficiency and energy-efficient advanced treatment process to solve this problem.In this paper,macroporous resin is applied in sewage advanced treatment according to the treatment status of a sewage plant which deal with industrial+municipal wastewater in Shandong province and a lot of relevant research.The adsorption process,influencing factors,adsorption mechanism,etc are analyzed so as to provide reference in practice.The experiment to explore the comprehensive analysis shows that:1.The adsorption effect of PVA and other pollutants with D3520 showed the most close to powdered activated carbon among the selected six kinds of macroporous resins(D280,DA201,DA-201,AB-8,D3520,D3520 and XAD-2),and the color removal effect is good,the CODcr adsorption capacity of up to 15.6mg/g.2.D3520 resin adsorption process showed a more pronounced two step adsorption.Its adsorption rate was fast in the beginning and then slow down until reach the adsorption equilibrium state in 240 min.The concentration of CODcr in mixed wastewater decreased from 95.31mg/L to 35.54mg/L,the removal rate of CODcr reached 62.7%,the chroma removal rate is as high as 95%.3.Increasing the initial concentration of mixed wastewater could Promote the adsorption capacity of D3520.D3520 resin adsorption effect increased with the pH value increased,when the mixed wastewater pH value is weakly alkaline,resin adsorption capacity increases little continue to enhance the pH value,and the adsorption effect showed a similar trend at the selected temperature range.Combined with the relevant emission standards and the actual operation requirements,selected initial concentration 100mg/L,pH value 8,the temperature of 25? for subsequent adsorption conditions.4.The isothermal adsorption experiments showed that the Langmuir isotherm equation can better describe the adsorption process of D3520 resin for pollutants of PVA in mixture wastewater.The adsorption process belongs to a single molecular layer physical adsorption,and the adsorption is preferential adsorption,easy to occur.5.The adsorption process of PVA in dyeing mixed wastewater with D3520 resin can be spontaneous,and its free energy changes are negative((27)(35)G0).The adsorption enthalpy change between 3~6kJ/mol(less than 40kJ/mol),suggesting that the adsorption process of D3520 resin has the obvious characteristics of the physical adsorption.(29)(35)S0indicates the resin adsorption process was of entropy increase.6.The kinetic analysis indicated that the adsorption process of resin is controlled by surface film diffusion of the resin and internal diffusion channels.The slow pore diffusion adsorption process of D3520 resin becomes the rate limiting process.7.It has optimum regeneration effect using 50% ethanol + distilled water and 5% hydrochloric acid + distilled water,distilled water and 5% sodium hydroxide as regeneration process.8.Controlling sample flow rate 0.24m/h,the resin bed height to diameter ratio 2:1,adsorption temperature 25 degrees centigrade in the fixed bed dynamic adsorption process,the adsorption effect of CODcr in wastewater is better.And controlling desorption control rate 4.8cm/h,desorption temperature 25 degrees can recieve the optimum desorption effect.And after 5 times of repeated adsorption-desorption experiments,the removal effect of CODcr can still maintain the minimum average 79.5% and more than 95% chroma removal efficiency,which indicates that the D3520 has stable treatment effect in dealing with mixed dyeing wastewater. |
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