Functional Modification Of Rectorite Composites And The Adsorption Study Of Inorganic Pollutants In Wastewater

Rectorite?REC?is a sort of natural clay mineral.The interlayer cations can be easily exchanged with other cations from the environment.Therefore REC exhibits the excellent adsorption capacity to remove cationic metals.When it was modified,the adsorption capacity will become more stronger.However,it is poor to remove anions and neutral organic compounds.If the rectorite are modified well,it will has great pothential in wastewater treatment.Such as changing surface area,interlayer spacing and exchangeable ability.Firstly,the rectorite?REC?/carbon composites?RECCs?were prepared with hydrothermal carbonization using starch as carbon source and REC as the template.RECCs were modified with carbon disulfide?CS₂?to obtain RECCx anthate?RECCX?composites.The adsorption process of Pb²⁺was investigated.The maximum adsorption capacities could reach 225.7 and 431.0 mg/g for RECC and RECCX respectively.Secondly,Carbon materials with many oxygen containing groups can reacted with trisodium trimetaphosphate to obain phosphate ester groups on the REC/carbon composites.Xanthate groups and Pb²⁺can form good chelation,which can improve the adsorption capacity of Pb²⁺.In addition,RECCP showed advantageous selectivity towards Pb²⁺over other metal ions(Cu²⁺,Ni²⁺,Co²⁺and Cd²⁺)and still removed above 90%Pb²⁺at the initial trace Pb²⁺concertation?0.5 mg/L?.The maximum adsorption capacity could reach 258.4 mg/g for Pb²⁺RECCP.Lastly,in order to improve the removal ability towards anion by rectorite,Polypyrrole?ppy?were introduced onto the layers of rectorite to fabricate rectorite/ppy composite.Due to the ppy with positive charge,it can form electrostatic interaction with the anion.When the magnetic Fe₃O₄ were introduced to the rectorite layers,it is favorable for separating the adsorbent form aqueous solutions.The maximum adsorption capacity could reach 105.0 mg/g for NO₃^-and97.23 mg/g for PO₄^3-.