Preparation Of Porous Materials By Breath Figure And Immobilization Of Bacteria For Phenol Removal

Polymer porous materials prepared by respiratory patterning have various advantages such as homogeneous pores,tight alignment and modifiability.The materials prepared and modified by respiration patterning method have achieved certain research achievements in the fields of chemistry,medicine,and biology,but few applications in the environmental field have been reported.In this study,porous materials prepared by respiratory patterning method were used to immobilize bacteria,prepare membrane reactors and insulation materials,and achieve efficient phenol degradation of bacteria in harsh environments such as high acid,heavy metal ions and low temperature.The details of the study are as follows.（1）Biofilm-membrane reactor（BF-MBR）has the advantages of high organic pollutant removal efficiency and low energy consumption,which provides a good way for wastewater treatment.bf-mbr consists of membrane assembly and carrier,and the carrier of membrane reactor faces the challenges of high cost and low adsorption efficiency when used for wastewater treatment in the long term.In this study,porous membranes were prepared using the respiration pattern method,and microorganisms were later assembled in them to construct the membrane reactor.The membrane reactor exhibited an excellent rate of phenol degradation(23.08 mg·L^-1·h^-1)compared with that of free bacteria(15.7 mg·L^-1·h^-1)compared to free bacteria(15.7 mg·L^-1·h^-1).The membrane reactor can effectively increase the enzymatic activities of phenol hydroxylase and catechol 1,2-dioxygenase,the key enzymes of phenol metabolism,and reduce the activities of antioxidant enzymes SOD,CAT and POD,which can efficiently enhance the degradation rate of phenol in the membrane reactor.In addition,the membrane reactor has good stability at a wider p H（3-8）and degradation efficiency is 5-8 times higher than that of free microorganisms.Under the stress of heavy metal ions,the membrane reactor still had a good degradation rate,which was 3-6 times higher than that of free bacteria.This method provides a new way to prepare cheap,efficient and stable membrane reactors.（2）The complex environment of phenol-containing wastewater makes it difficult for microorganisms to achieve efficient degradation of phenol at high concentrations and low temperatures.The multi-stage pore structure of polyurethane（BF-PU-PI）was prepared by respiratory patterning method,and Bacillus cereus ZWB3 was effectively immobilized by electrostatic force.2400 mg/L phenol was degraded by BF-PU-PI immobilized bacteria at 37℃,and the degradation rate was increased by 14%-41%compared with that of free bacteria.By measuring the metabolic pathway and metabolic enzyme activities of Bacillus cereus ZWB3,the phenol hydroxylase and 1,2-dioxygenase activities within BF-PU-PI increased by 180%and 69%compared to the free bacteria,while the antioxidant enzyme activities were significantly lower.At 15°C,BF-PU-PI immobilized ZWB3 could effectively increase the degradation rate of phenol and had relatively lower antioxidant enzyme activity compared to free bacteria.In addition,the free fatty acid content of BF-PU-PI immobilized bacteria was only 75%of that of free bacteria,and the extracellular polysaccharide content was 76%,indicating that BF-PU-PI could provide good insulation performance for ZWB3 to ensure that the bacteria could survive in complex environments and achieve efficient treatment of phenol at low temperatures.In summary,the porous material prepared based on respiratory patterning method can immobilize the bacterium,improve its metabolic enzyme activity under high phenol concentration conditions and its ability to survive in complex environments,achieve efficient degradation of phenol,and provide more potential value for its use in environmental remediation.