Synthesis Of Magnetic CMC-CoFe₂O₄Compounds And Research On The Phosphate Removal And Recovery From Wastewater

Because of the lack of phosphorus resource and phosphate pollution which led to thecontradiction between the eutrophication. Thus, pursing of technologies for phosphorusremoval and recovery from waters can not only improve the water quality and lighten thecontamination, but also realize the phosphorus recycling and sustainability, relieve thedeficit of phosphorus resource.Recently, a number of studies have been focused on adsorption for phosphorusremoval and recovery. However, the method of adsorption has greatly confined wideapplication of it. And desorption of the adsorbent, regeneration, solid-liquid separation,recycling and phosphorus recovery become difficult. This article used precipitation toprepare CoFe₂O₄-carboxymethyl cellulose （CMC） composite material which is asadsorbent, researched on the adsorption performance of this adsorbent to wastewatercontaining phosphate, and magnetic separation and recovery. Inspected the influence toadsorption reaction of adsorption reaction time, the pH value of phosphorus wastewater,adsorption dosing quantity, the initial concentration of phosphorus wastewater with thebest performance for the CMC-CoFe₂O₄absorbent. The article aslo researched onadsorption selective in the best adsorption condition, meanwhile, it also analyzes theregeneration and the desorption of absorbent. The phosphorus can be converted toCa5（OH）（PO4）3recover the phosphorus of desorption. And the CMC-CoFe₂O₄wascharacterized by SEM, XRD, FT-IR.The results of this experiment showed that the reaction time of optimum adsorptionis90min, the optimal initial pH value of phosphorus wastewater is2.5, the best dosingquantity of adsorbent is2.5g/L. By fitting the secondary dynamics equations of theadsorption from CMC-CoFe₂O₄to phosphate, it indicated that the adsorption reactionaccorded with first order kinetic equation. By fitting the isothermal type of the adsorptionfrom CMC-CoFe₂O₄to phosphoric, it showed that the adsorption isothermal of differenttemperature accorded with Langmuir model, raising temperature is advantageous tophosphate adsorption; The Gibbs free energy of the reaction is negative value, whichshowed that adsorptive reactions could be spontaneous. The adsorption selectivity ofseveral kinds of common anion and cation is that CO32->SO42-> Cl->NO3-; Mg2+> Ca2+> NH4+; and cation> anion. And anionic and cationic in natural water bodies rarely effectthat adsorbent adsorb phosphorus in wastewater. The experiment confirmed that practicalapplication of deshorption solution concentration of5%NaOHand the regeneration liquidis15%NaNO3. The phosphorus of actual deshorption solution of phosphorus recoveryexperiment, The recycling of phosphorus is60min, Ca: P=2, pH=13, the initialconcentration of the solution of phosphorus of50mg/L, phosphorus recovery rate was96.65%, the resolution rate of97.3%. The results of the characterization of SEM, XRD,FT-IR mainly make clear CMC-CoFe₂O₄for pure single spinel, adsorption of phosphorus,desorption, regeneration, the effect of the recycling of phosphorus is perfective.Based on CMC-CoFe₂O₄magnetic adsorbent at room temperature with theoptimum adsorbent influence factors for adsorption of10mg/L’sphosphorus wastewater,the removal rate was95.24%, the saturated adsorption capacity of3.8096mg/g, residualphosphorus concentration is0.0147mg/L, the treatment of phosphorus wastewaterreaches the national primary standard of0.5mg/L, the results show that CMC-CoFe₂O₄effectively achieve adsorption, desorption, regeneration and repeated cycle of theimplementation of the adsorbent.