Study On Dye Adsorption/regeneration Performance Of Adsorbent Prepared From Latex Production Sludge

The latex-production wastewater contains organic pollutants,such as polymeric latex and unreacted monomers,which is usually treated by coagulation method.The concentration of organic matter in the coagulated sludge is large,so that it is not easy to be degraded.If sludge is prepared into adsorbent for reasonable utilization,it will have broad application prospects.In this paper,sludge from latex production was used as raw material to prepare adsorbents by direct carbonization?DC?and NaHCO₃ impregnation carbonization?N-DC?,and the adsorbents is used to deal with cationic blue X-GRRL dye solution.Considering that all kinds of factors have influence on the decolorization effect of the adsorbents,such as adsorbent dosage,initial dye concentration,adsorption time and pH value of solution and so on,to have further confirmation for the adsorption mechanism.The microstructure of adsorbent was analyzed by various instruments.In addition,the thermal regeneration and adsorption properties of adsorbents prepared by N-DC method were also preliminarily explored.The research contents of this paper were as follows:?1?The adsorbents were prepared by DC and N-DC methods.The effects of carbonization temperature,carbonization time and adsorbent sizes on adsorptive capacity were investigated.And the optimum preparation conditions of DC method were determined.At the same carbonization temperature and time as the DC method.The effects of particle size,NaHCO₃ impregnation ratio and impregnation time on the adsorption efficiency were investigated.The results showed that at 700?for 120 min,NaHCO₃ impregnation ratio 1.5:1 for 30 min,the two adsorbents?particle size less than0.075 mm?prepared by the DC and N-DC methods had the best adsorption effect on dye solution.?2?The microstructures of two adsorbents were analyzed by various instruments,and the effects of adsorbent dosage,initial dye concentration,adsorption time and solution pH on adsorption were studied.The results showed that the specific surface areas of the two adsorbents were 177.84 m²/g and 313.39 m²/g,respectively,and the pore structure was well developed.And it had relatively developed pore structure.The decolorization rate of the solution was up to 98.30%and 98.78%,respectively,and the adsorption amount of cationic dye were 204.80 mg/g and 411.57 mg/g with temperature of 25±0.10?,oscillation frequency of 150 r/min,adsorbent dosage 1.20 g/L and 0.60 g/L,initial dye concentration of 250 mg/L,adsorption time 240 min,and pH value 5.47.?3?Kinetic and hermodynamic experiments show that the adsorption process can be described by quasi-second-order kinetics,intraparticle diffusion model and Langmuir isothermal adsorption model,respectively.?G⁰<0,which indicated that the adsorption can be carried out spontaneously.?H⁰>0,indicating that the adsorption process is endothermic reaction.?S⁰>0,indicating that the confusion degree of solution system increases.?4?The optimal thermal regeneration temperature,time and heating rate of adsorbent?N-DC method?were determined by response surface methodology.And repeated experiments were carried out.The results showed that the regeneration efficiency of adsorbent was the highest at 550?for 60 min and heating rate 10?/min.After five experiments,the decolorization rate of cationic blue X-GRRL solution could still be more than 80%at the dosage of 0.60 g/L,and the decolorization effect was better.