The Removal Of Bisphenol Compounds In Water Environment By Coconut Shell Biochar Immobilized TTNP3

Bisphenol A(BPA)and bisphenol S(BPS)have attracted worldwide attention due to their wide usage,degradation-resistant,high detection frequency,and has threatend to human health.Therefore,the exploration of methods for removing bisphenol A and bisphenol S in aqueous environment has attracted wide attention from researchers worldwide.Biochar is widely used as a low-cost,high-efficiency biomass material to remove bisphenol A from the environment.Studies have shown that Sphingomonas sp.strain TTNP3 can effectively degrade bisphenol A.And biochar adsorption and microbial degradation have attracted much attention due to their low cost and environmentally friendly removal efficiency.However,because biochar is mainly dominated by adsorption,it cannot completely remove target pollutants.The concentration and activity of the free bacteria TTNP3 in the target range are difficult to control.Therefore,it is imminent to find a way to remove BPA and BPS in water environment thoroughly and efficiently.In this project,coconut shell biochar was used as an adsorbent to explore the structure and physicochemical properties of biochar.The adsorption properties and influence factors of BPA and BPS were studied.The strain Sphingomonas sp.strain TTNP was used as a representative microorganism to study its effect on BPA and BPS.Degradation properties and influence factors of BPA and BPS;and then applied Sphingomonas sp.strain TTNP3 immobilized in coconut shell biochar to remove bisphenol A bisphenol S in the aqueous environment.Conclusions are as follows:(1)Coconut shell Biochar has a porous structure with a large specific surface area and a distribution of oxygen-containing functional groups on the surface,which is negatively charged.The coconut shell biochar has good adsorptive properties for BPA and BPS.The Langmuir maximum adsorption of BPA is 73.53 mg L-1,and the Langmuir maximum adsorption of BPS is 105.26 mg L’1.Langmuir fit the isotherm dara better than Freundlich,which shows that the process of BPA and BPS sorbed on coconut shell biochar is mainly controled by monolayer uniform surface adsorption.The pseudo-second-order kinetics model fit the kinetic best,and the adsorption rate was BPS>BP A.The effect of temperature and ionic strength on the adsorption effect is not obvious,and pH has a great influence on the adsorption process.(2)The strain TTNP3 has high tolerability and can still be alive and degrading in the environment with high BPA/BPS concentration(100 mg L-1).In a 30mL system with a contaminant concentration of 40 mg L-1 and a bacterial concentration of 3.3*108 CFU mL-1,the degradation rate is relatively fast.Under experimental conditions,BPA was totally degraded at about 6h and BPS at about 36h.BPA was degraded faster than BPS.BPA was degraded 80%within 3 h and BPS was degraded 80%within 14 h.The effect of temperature and pH on the TTNP3 degradation was more obvious.Among them,the degradation rate was the highest under neutral conditions at 30℃.(3)The results of the batch experiments showed that the removal rate of BPA and BPS in the aqueous environment by the immobilized microorganisms was 3-5 times higher than that of the biomass alone.The results of column experiments using coconut shell biochar as adsorbent showed that the removal rate of BPA and BPS increased as the amount of biochar increased from 0.05g to 0.2g;the flow rate had a greater influence on the removal rate,with the increase of the flow rate,the removal rate of BPA and BPS decreased.Biochar immobilized TTNP3 column experiments had the higher removal efficiency and longer breakthough time of bisphenol compounds than coconut shell biochar contaminants,which were BPA from 810 minutes to 2160 minutes,BPS from 900min to 1620 minutes,respectively.