The Extraction Of Aniline And 4-MP From Wastewater By Switchable Pickering Emulsion

The emulsion stabilized with solid particles is termed as Pickering emulsion,which has been used to encapsulate liquid acid/alkali catalysts to construct cascade reaction systems,Pickering emulsion polymerization to prepare bacterial imprinted polymers,and porous foam materials and simulated natural antigen systems.However,there are few studies on the application of switchable Pickering emulsion prepared by functional microparticles to the treatment of organic wastewater.This paper is based on the stability,emulsification new energy,stability/demulsification of two switchable Pickering emulsions prepared based on photosensitive and magnetic particles.The mechanism,stimulus responsiveness and other aspects have been systematically studied,and both of them are introduced into the external aqueous phase to construct a photosensitive or magnetic Pickering emulsion liquid membrane（PELM）system,and applied to the extraction of aniline and 4-methoxyphenol solutes,respectively,to provide a certain theoretical basis and technical support for the application of organic wastewater treatment.（1）In the preparation of photosensitive Pickering emulsion,trichloro（dodecyl）silane was grafted onto the surface of the synthesized Ti O₂particles,and the catalytic degradation of the surface by UV light led to the degradation of long-chain silane on the surface into short chains,which caused its surface wettability changed,and the three-phase contact angle test showed that the wettability changed from 140.39°to107.95°.It was used as an emulsifier and petroleum ether to be mixed into the oil phase,and formed Pickering emulsion with diluted hydrochloric acid solution,and slowly introduced photosensitive emulsion into the external aqueous phase containing aniline to construct PELM system.The experimental results showed that the concentration of s-Ti O₂is 2%wt,oil-water ratio 1:1,rate of preparaed emulsion15000rpm,emulsification time 2min,HCl concentration 0.6mol/L,emulsion-water ratio 1:10,stirring rate 200rpm,external water phase p H under the condition of 8,the best extraction rate of 83.73%was obtained within 20 min for the external aqueous phase with a concentration of 1000mg/L aniline.（2）Based on erucic acid-modified nano-Fe₃O₄particles,the three-phase contact was tested at 109.5°,and then used SEM,FT-IR,XRD,TGA to characterize their morphology,surface properties and recycling property.The mixture of magnetic particles,green/non-polluted rapeseed oil and TBP carrier was used as the oil phase,and the W/O Pickering emulsion was stabilized with the internal aqueous Na OH solution.The particles concentration and oil-water ratio were investigated by microscope and macro static analysis the main factors such as rate and time of preparaed emulsion,Na OH concentration affect the stability,emulsification performance and 4-MP extraction efficiency of the emulsion.After screening one by one,the best suitable operating conditions for constructing the PELM system were selected,namely 2.5wt%particle concentration,oil-water ratio 2:1,Na OH 0.5mol/L concentration,stirring rate 15000rpm,emulsification time 5min,emulsion-water ratio1:5,the stirring rate of 250rpm,the concentration of 30%TBP,and the p H value of the external water phase was 1.For the external water phase with 4-MP concentration of 750mg/L,the optimal extraction rate was 85.52%within 5 minutes.Subsequently,the recycling property of the oil phase and the particles was investigated,and it was found that the PELM system constructed with the oil phase and the particles re-used 4times could achieve an extraction rate of 76.02%within 10 minutes,demonstrating good recyclability.