Preparation And Properties Of Efficient Absorbents For Benzene Series

With the development of industry,benzene series have been widely applied to various fields,while serious environmental pollution and security risks are brought about in the production,transport or use.It’s imminent to manage and control the serious situation.Absorption was a simple and effective treatment method in control of benzene series contamination.In this paper,a series of efficient synthetic absorbents and efficient composite absorbents for benzene series were designed and prepare,which had good pertinence,large absorbency,fast absorption rate,low surface stickiness after absorption and good recycling performance.The absorbents could be used for the treatment of industrial wastewater containing benzene series and the emergency absorption of the solvent leakage in chemical production.First,the efficient synthetic absorbents were prepared by suspension polymerization using butyl acrylate(BA)and styrene(St)as comonomers,and divinylbenzene(DVB)as crosslinker.The effects of monomer mass ratio,crosslinking structure,initiator(BPO)dosage and dispersant(PVA)dosage on the absorbency of absorbent were mainly investigated.The results showed that:when m(St):m(BA)= 3:1,the absorbent had gel strength and low surface tackiness after absorption.With the increasing of crosslinker dosage,gel fraction increased but average molecular weight between crosslinks of absorbent decreased.When the initiator dosage was 0.50%and the dispersant dosage was 0.17%,the absorbency was good and particles size was suitable.The properties of the efficient absorbent prepared under the optimization formula were:the absorbency of 16.99g/g(toluene)and 15.43g/g(xylene);the relative absorption rate of 0.86g/g(toluene)and 0.79g/g(xylene);and 9.49g/g for the absorption capacity of toluene floating on water.Based on the efficient synthetic absorbent,the absorption process,release property and regeneration performance were researched.The effects of crosslinking structure,monomer mass ratio and temperature on the absorption kinetics and release kinetics were investigated.It was found that there was a certain relationship between the absorption rate and absorption kinetic constant K and monomer mass ratio,crosslinking structure,and absorption temperature.The absorption process consisted with quasi first-order kinetic equation.There was a certain relationship between the release rate and the calculated diffusion coefficient D and crosslinking structure,monomer mass ratio,and release temperature.By fitting the experimental data,a simple accurate release kinetic equation of absorbent was obtained.Desorption and regeneration of the absorbent was carried out with water distillation process.Both the recovery rates of benzene series and absorbent were high,and the regenerated absorbents could maintain the original absorption level.With the silica gel as skeleton materials,a thin layer of efficient synthetic absorbent polymer was coated on the skeleton surface to get the efficient composite absorbents with core-shell structure by emulsion polymerization.The effects of emulsifier(SDS)dosage,monomer concentration(m(St):m(BA)= 3:1),crosslinker dosage and initiator dosage on the absorbency of the composite absorbents were mainly investigated.It was found that the change of emulsifier directly affected the coating thickness of composite absorbents,and then affected the absorbency and the state of products.Crosslinker dosage affected the crosslinking density and the coating effect of copolymer coating layer,and then affected the absorbency of composite absorbents.When the emulsifier concentration was 2.5g/L,monomer concentration was 40g/L,crosslinker dosage was 2.0%(the total mass of the monomer)and the initiator dosage was 1.0%,the composite absorbent had good absorbency and the copolymer coating layer on silica gel surface was desirable.