Removal And Recovery Of As(?) From Waste Water With Prepared Modified Graphite Oxide And Phosphorene Adsorbents

As?III?and As?V?are hazardous for human health seriously.It will cause organs pathological changes.Arsenic is more toxic than arsenate.Therefore,arsenic pollution is paid attention by all people in the world.Adsorption method was used in this study since it could be operated easily and stably.The adsorption capacity is large and convenient for regeneration with high performance adsorbents,although small equipment is used for arsenic treatment.It has great meaning for improving people's living quality and ensuring water safety with heavy metal removal.Titanium nano tube?TNT?has good adsorption for arsenic,but its mechanical strength is weak.In addition,it is difficult to separate and recovery heavy metal from water.Combination of TNT with other materials is used to improve the efficiency of adsorption and separation in this study.Furthermore,Graphene oxide titanium nano tube?GO-TNT?was supported on Magnetic nano particle?MNP?and phosphorene?PN?to prepare adsorbent composites for As???adsorption in aqueous solution.The surface feature,skeleton structure,specific surface area,pore size,gap energy,function group and zero potential of composites were analyzed.The effects of adsorption conditions such as pH value,temperature,GO content,adsorbent dosage,pollutant concentration and compitetion ions in solution were also analyzed with uniform design and single factor experiment.In addition,the recycling performance of composite was investigated.This work illustrated three kinds of useful materials for further research about adsorbents modified,prepared and reused for arsenic removal.The main conclusions are listed as follows:1.GO,GO-TNT and MNP-GO-TNT were synthesized by hydrothermal method succefully.Besides,phosphorene was also synthesized by exfoliation method succefully.The structures of GO,GO-TNT and MNP-GO-TNT are multi layers with sheet shape.From AFM results,the thick of GO,GO-TNT and MNP-GO-TNT is 100,8 and 5.6 nm,respectively.From N2 adsorption/desorption analysis results,the surface area of TNT,2%GO-TNT,5%GO-TNT and 10%GO-TNT is 332,145,134,128 and 125 m2 g^-1,respectively.2.The best component ratio of MNP-GO-TNT is MNP of 16.85%-GO of 66.29%and TNT of 16.85%,obtained from response surface methodology.The reaction rate is 0.057 mg L^-1 min^-1 for 1.0 mg L^-1 of As???adsorption with optimal adsorbent.3.The optimum operation condition for As???removal with 5%GO-TNT,MNP-GO-TNT and PN is under pH 3,temperature of 45 ?,initial As?III?concentration of 1 mg L'1,and dosage of 0.1 g L^-1.The removal efficiency for As?III?is 90,59 and 90 with using GO-TNT,MNP-GO-TNT and PN,respectively under pH 7,temperature of 45 ?,initial As???concentration of 1 mg L'1 and dosage of 0.1 g L^-1,.The maximum adsorption capacity calculated from Langmuir with 5%GO-TNT?MNP-GO-TNT and PN is 20.0,20.3 and 24.2 mg g^-1,respectively.The adsorption process of 5%GO-TNT,MNP-GO-TNT and PN is conformed with a pseudo-second-order kinetic model.As???adsorption behavior with 5%GO-TNT,MNP-GO-TNT and PN is nonspontaneous from the results of thermodynamics analysis.As?III?is adsorbed with 5%GO-TNT,MNP-GO-TNT and PN,in randomness during the adsorption process.4.NaOH of 0.1 M was used in regeneration experiment to recycle 5%GO-TNT and MNP-GO-TNT.After recycling of 5 times,the removal efficiency of 5%GO-TNT composite is slightly decreased.The adsorption capacity was decreased 11.2%after comparing with that with original adsorbent.Besides,1 mg L^-1 As?III?adsorption performance with MNP-GO-TNT is almost the same after recycling for 5 times.The adsorption capacity with MNP-GO-TNT is only decreased 12%after comparing that with of original adsorbent.It means these materials are suitable for recycling.5.According to the characteristics before and after As?III?adsorption,the adsorption mechanism could be illustrated for 2 kinds of routes.First,Ti-OH and Fe-OH groups are reacted during adsorption process,and-OH is replaced by As???.The main reaction in the adsorption mechanism is chemical adsorption.Second,-COOH and-C=O-in GO are bonded with H+,indicating it's a physical adsorption.The adsorption mechanism of PN indicates the-COO function groups on the surface of phosphorene are bonded with As???after adsorption,and illustrates it's a physical adsorption.