| Heavy metals and aromatic harmful substances are the key control targets of water pollution control.Among all kinds of sewage treatment methods,adsorption method is widely used and is still the most practical treatment technology at present.The use of natural cheap and readily available graphite as raw material to obtain excellent performance of water treatment adsorbents has always been a research focus in the application of environmental pollution treatment materials.In recent years,graphene materials have attracted attention in the research and development field of water pollution treatment materials due to their rich surface active groups and strong adsorption capacity.In this paper,graphene oxide(GO)was prepared by the oxidation of graphite powder as raw material,and the magnetic graphene oxide(MGO),an adsorption material suitable for sewage treatment,was further obtained by magnetization.To enhance water treatment material recycling performance,then MGO style mixed with sodium alginate(SA)polymer molding to preparation has good comprehensive performance of magnetic graphene oxide/sodium alginate composite material(MGO/SA),and study the series of graphite modified products in containing heavy metals(Cr(?))and aromatic hydrocarbon(nitrobenzene)application and experiment of wastewater treatment adsorption dynamics and thermodynamics theories.The research contents and results are as follows:1.Magnetic graphene oxide adsorption material(MGO)preparation experiment.Product adsorption ability strong or weak to Cr(VI)adsorption rate size measure,first through the single factor experiment investigation temperature,processing time and dosage of graphene oxide containing Cr(?)wastewater by adsorption effect,the influence of the process The optimal preparation condition is : the temperature is80 ?,the processing time is 4 h,the dosage of graphene oxide,0.7 g for MGO style of Cr(?)adsorption rate was 98.20%.The results showed that Fe-O groups appeared on the surface of MGO and fine magnetic particles were evenly distributed.The roughness increased,indicating that the magnetic load was successfully deposited and MGO was formed.In the XRD pattern,there are obvious characteristic peaks at the positions of 30.70°,35.82°,43.30°,53.46°,56.97° and 63.88° in 2?,respectively,corresponding to the diffraction peaks(220),(311),(400),(422),(511)and(440)of the pure cubic spike structure of ferric oxide,with a typical s-type hysteresis loop and a saturation magnetization of 27.7591475 emu/g,which can be easily separated in aqueous solution.As the p H value of the solution increases,the surface charge of MGO changes from positive to negative,and the isoelectric point is 3.0.2.Application experiment of MGO on water pollutant treatment.experimentalconditions,the pollutants Cr(?)adsorption rate with the increase of the dosing quantity and processing time;Cr(?)adsorption effect is greatly influenced by p H value,the optimum p H value is 2.The adsorption rate of nitrobenzene increased with the increase of p H value,and the optimal p H value was 2.Under temperature 25 ?,the processing of the initial concentration of 10 mg/L Cr(?)and nitrobenzene wastewater,the best experimental conditions for: MGO style dosing quantity,p H value,the processing time were 0.15 g and 0.2 g,2 and 2,180 min and 180 min,adsorption rate was 96.93% and 98.79%.Preliminary study the MGO style adsorption dynamics process,setting conditions,MGO style to Cr(?)and the adsorption process of nitrobenzene better agreement with quasi level 2 dynamic model and the correlation coefficients of above 0.99.Hydrochloric acid solution to reach adsorption equilibrium desorption experiment of MGO,the Cr(?)and nitrobenzene desorption rate are 70.4% and 73.6% respectively;The desorption MGO again for sewage treatment,after the adsorption rate for Cr(?)and nitrobenzene were 71.1% and80.05% respectively.MGO compared with sewage treatment of activated carbon powder experiment that MGO adsorption of Cr(?)and nitrobenzene ability.3.Magnetic graphene oxide/ Sodium alginate(MGO/SA)preparation experiment.Through single factor experiment investigation content of MGO,Na Cl content and curing temperature on the absorption rate of the Cr(?)wastewater,choose curing time is 3 h;Orthogonal experimental conditions as follows: the MGO is 0.45 g,Na Cl was 2.4 g,curing temperature 25 ?,the composite product MGO/SA of microspheres Cr(?)adsorption rate was 97.73%.The surface is rough,showing irregular network structure,and the interior has fold mesh lamination.It has a typical S-type hysteresis loop with a saturation magnetization of 2.679082781 emu/g,which can be rapidly separated from aqueous solution.When the p H value gradually increased,the surface charge of the composite microsphere changed from positive to negative,and the isoelectric point was 2.6.Obviously,the characteristics of the composite products are beneficial to improve the comprehensive application effect of sewage treatment.4.Application experiment of MGO/SA in water pollutant treatment.Experiment conditions,adsorption rate with microspheres dosing quantity and processing time increases with the increase of adsorption of Cr(?)effect along with the increase of p H decreases,the optimum p H value is 1;The adsorption rate of nitrobenzene is greatly affected by p H value,and the optimal p H value is 3.Under 30 ?,initial concentration of 10 mg/L Cr(?)and nitrobenzene wastewater,the optimum processing conditions were as follows: microspheres dosing quantity of 0.3 g and 0.3g,p H value of 1 and 3,the processing time of 270 min and 270 min,the adsorption rate of 97.28% and 99.69%.MGO/SA adsorption process kinetics experiment found that under the condition of setting,MGO/SA to Cr(?)and the adsorption process of nitrobenzene better agreement with quasi level 2 dynamic model and the correlation coefficients of above 0.99.Hydrochloric acid solution to reach adsorption equilibrium of MGO/SA desorption experiments,Cr(?)and nitrobenzene desorption rate are72.5% and 76.3% respectively;After the desorption MGO/SA repeat for Cr(?)and nitrobenzene wastewater treatment,the adsorption rate can reach 90.3% and 93.7%.The stability experiment of MGO/SA showed that the mass of the composite productchanged little when the p H value was 1-13,and the mass only decreased by 2.2%even at the temperature of 50?.Under the condition of soaking for 1-9 weeks,the mass difference measured in the fifth week of soaking was the largest,and the mass decreased by 0.0159 g,which was 1.6% before soaking.Therefore,the composite product had good stability. |
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