Preparation And Properties Of Modified Materials On Adsorption Of Boron

After the occurrence of boron environmental emergencies,boron will diffuse rapidly with water flow.Not only has it caused serious pollution of the water environment,but also posed a serious threat to the safety of drinking water,in order to reduce the boron concentration below the standard of living water sanitation(GB 5749-2006)in the shortest possible time.it Therefore,it is of great significance to find boron adsorption material with high adsorption time,large adsorption capacity and low price.In this paper,the adsorption effect of activated carbon and meglumine on 2.5mg/L boron solution was studied.Then using ferric nitrate,bentonite,activated carbon,phosphoric acid and meglumine as raw material,preparation of Bent-Fe and Bent-NMDG and PC-NMDG and NMDG-C four composites were synthesized to find the best material for adsorption of boron.The use of different means of material characterization is to analysis physicochemical properties of the best material.The effects of different speed,adsorption time,p H value,temperature and initial concentration of boron were investigated by the dynamic adsorption experiments.The adsorption of boron by the best material was studied by adsorption kinetics and thermodynamic model,and the adsorption mechanism is discussed.The main results are as follows:(1)The removal rates of boron from activated carbon and meglumine were 33.20%and 76.80%respectively,which could not meet the requirements of emergency treatment.The removal rates of Bent-Fe,Bent-NMDG,PC-NMDG and NMDG-C were 8.00%9.60%,56.40%and91.00%respectively,and when the mass ratio of active carbon and methylamine is 1:0.20 and the solution pH is neutral,the NMDG-C is optimal.(2)Automatic specific surface meter showed that the NMDG-C BET surface area and pore volume were decreased than activated carbon by77.20%and 85.90%respectively.The SEM images show that the surface became loose when the activated carbon was modified,and the surface diameter of the material increased with the addition of boron.EDS and XRD analysis showed that no other impurities were introduced in the modification process and the methylamine was successfully loaded onto the activated carbon.Fourier infrared spectroscopy shows that NMDG-C contains more hydroxyl groups,which is beneficial to the adsorption of boron.(3)The adsorption effect of NMDG-C increased significantly,The maximum adsorption capacity occurred at pH 7 and the removal ratio reached 90.59%for 30mL boron concentration of 2.5mg/L and adsorbent dosage of 1.5g at 15?.The adsorption reached equilibrium within 30min.The adsorption process fitted well with the Langmuir isotherm model and pseudo second-order kinetic model(r~2?1),and the saturated adsorption capacity for boron was 1.16mg/g.Adsorption process was easy to adsorb.KCl solution was used as the desorption agent,and NMDG-C can be used repeatedly.