Study On Preparation Of Lanthanum Modified Hydrogel And Enhanced Phosphorus Removal Efficiency Of SBR Process

Among all the elements circulating in the biosphere,phosphorus is the rarest element,and phosphorus is also a basic part of life,but phosphorus on the land has been lost.Nowadays,biological phosphorus removal commonly used in sewage treatment plants has the defect of unstable effluent,so it is often combined with chemical precipitation phosphorus removal technology.However,this treatment method often produces a large amount of excess sludge and does not realize the recovery of phosphorus.The adsorption method has the advantages of good phosphorus removal effect,low cost,and phosphorus recovery.Other phosphorus removal methods cannot be replaced.Because of its large volume,hydrogel-type adsorbent is easy to separate from sewage and can realize the recovery of phosphorus.It is an adsorbent material worthy of in-depth study.The introduction of lanthanum can effectively increase the adsorption capacity of adsorbent for phosphorus.And under the low concentration condition,it can promote the growth of microorganisms.In summary,a new type of lanthanum-modified graphene oxide and alginic acid double network structure hydrogel material?GA-La?was prepared in this topic,and its structure,adsorption efficiency and SBR enhanced phosphorus removal The impact was studied.GA-La hydrogel characterization results show that the internal structure is cabbage-like,has a certain mechanical strength,is a mesoporous material,has a large specific surface area,and successfully adsorbs phosphate.And the maximum adsorption capacity is up to 239.6 mg P/g,which has a strong adsorption capacity for phosphate;as the p H increases,the adsorption capacity decreases,indicating that the adsorption capacity of the adsorbent is affected by the degree of protonation on the surface of the adsorbent.The order of influence is SiO₃^2->SO₄^2-=CO₃^2->NO₃^->Cl^-,in which the effect of SiO₃^2-on adsorption is much greater than other anions,the reason may be that silicon ions and lanthanum can form a stable complex;the adsorption process is in accordance with pseudo-two High-level kinetic model,indicating that chemical adsorption is dominant;the adsorption isotherm conforms to the Freundlich model,indicating that the adsorption process is dominated by multilayer adsorption;the adsorption thermodynamic result ?G is a negative value,indicating that the adsorption of phosphorus on the hydrogel is a spontaneous process,?H is a positive value,indicating that the adsorption process is an endothermic reaction,and ?S is a positive value,indicating that the entropy of desorption of water molecules increases than the decrease of entropy caused by phosphate adsorption.The results of SBR enhanced phosphorus removal efficiency show that the addition of low concentration of adsorbent has a slight promotion effect on the removal of COD in SBR.In contrast,the adsorbent enhances the removal effect of phosphorus in SBR very clearly,but when GA-La adsorbent When the dosage is greater than or equal to 40 mg/L,the phosphorus concentration of the SBR effluent is not much different,and it is less than 0.5 mg/L in line with Class A of the urban sewage treatment plant pollutant discharge standard.When the dosage of GA-La adsorbent is less than or equal to 40 mg/L,it will increase the PN content of EPS in the SBR system.As can be seen from the 3D-EEM results,it is mainly tryptophan-like protein and rot-like protein The content of genotropic substances is increasing,and the sludge particle size in the sludge properties will increase,SVI will decrease,MLVSS/MLSS will increase,PN/PS will increase,and Cell TP will decrease.The concentration of GA-La adsorbent will release a certain concentration of La³⁺,and low concentration of La³⁺ can stimulate the activated sludge to produce an enzymatic reaction,which will increase the activity and flocculation performance of the activated sludge,but will reduce the phosphorus accumulation in the activated sludge.