Preparation Of Novel Nano-adsorbent And Its Application In Treatment Of Organic Wastewater Containing Cr(?)

At present,with the continuous development in the chemical industry,the problem of environmental pollution is becoming more and more serious issues,especially the heavy metal Cr(?),which has a great harm to the environment and human health.In order to control heavy metal Cr(?)pollution,research and preparation of a series of new functional adsorption nanomaterials were carried out.The adsorptive nanomaterial has many new features compared with bulk materials,for example,the specific choice of adsorption and photocatalytic properties,in addition,the surface of nanomaterials are rich in chemical groups,the chemical properties are very actively.Micro-nanocomposites could be obtained through chemical modification strategies to provide them with multiple functions.Therefore,to explore the application of novel functional adsorption nanomaterials in the environment has become one of the focuses and hot spots of research workers.In this paper,we synthesized a series of novel functional adsorbed nanomaterials and modified materials to form multifunctional composite materials,which enhanced the high efficiency adsorption of heavy metal Cr(?)in water environment.However,single physical adsorption could not completely remove the Cr(?,adsorption method in essence had some restrictions.In response to this problem,this paper linked the function of adsorption nano-materials and microbial degradation or photocatalysis,so as to achieve the dual purpose of adsorption and degradation,to complete remove of heavy metals Cr(?).(1)N,N-dimethyl formamide(DMF)and heavy metal Cr(?)as the more difficult to remove in wastewater had lead lots of questions.In order to solve above problems,first,graphene oxide(GO)was prepared by Hummers oxidation,then,methacrylic acid(MAA)and n-butyl methacrylate(BMA)were modified on the surface of graphene oxide by a free radical copolymerization method to prepare a novel functional nanocomposite,the material has a larger specific surface area,could improve the selective adsorption capacity of heavy metals Cr(?)and DMF.By making a simple bucket model using the common carrier of copper meshs,the functional nanocomposites were then loaded onto the copper mesh surface by unending ultrasonic coating,the microorganisms used to degrade DMF(Paracoccus denitrificans)and Cr(?)(B.subtilis)are then encapsulated,finally,after hot melt glue gun sealing to achieve the efficient treatment of DMF and Cr(?).Experimental results showed that this strategy allowed for the complete removal of initial concentrations of 500 mg/L and 100 mg/L at 6 h and 9 h.And,this model could prevent the loss of microorganisms,in advance after three cycles of utilizations,this method still maintains 100 % removal efficiency.(2)The rapid development of the industry and the textile industry had resulted in serious environmental pollution,emissions of azo dye wastewater and heavy metal caused a huge threat for the human ecological environment.In response to the above focus,in this chapter,a kind of magnetic core-shell nanomaterials(Fe3O4@MIL-100(Fe))was parepared by the strategy of step by step method.The material had good biocompatibility and good adsorption capacity,After biological activation,the nano-material could be uniformly loaded onto the surface of the microorganism so as to achieve the adsorption and thorough degradation of water pollutants,degradation of different types of pollutants could be achieved by changing different types of microorganisms.In this paper,azo dye wastewater as a model to further study,the experimental results showed that Fe3O4@MIL-100(Fe)had a strong selective adsorption capacity,the dye degradation at 25 mg/L and 50 mg/L taked only 15 h and 25 h,and compared to the free microbial degradation efficiency had greatly improved.In addition,this magnetic nanoparticle composite could be separated under the action of an applied magnetic field,had a good circulation effect,and could be recycled and reused.(3)Aiming at the low efficiency of microbial degradation of heavy metal Cr(?),in this paper,spherical Ti O2 was prepared by a hydrothermal method,after alkaline hydrolysis to obtain a larger surface area of titanate nanobelts(UHTNs),the surface of UHTNs was loaded with a layer of Sn S2 to prepare a nano-material with a heterojunction structure of UHTNs@Sn S2.The nanomaterials could extend the recombination time of electrons and holes and could significantly reduce the forbidden band width of the catalyst to increase the photocatalytic time and thereby enhance the photocatalytic ability to degrade heavy metal Cr(?).Studies had shown that UHTNs@Sn S2 exhibited a very good photocatalytic reduction effect for Cr(?),the 50 mg/L Cr(?)solution could be completely reduced in only 25 min and the result could promote further research on degradation of Cr(?).