Efficient Heavy Metal Adsorbed From Water By The Artemia Egg Shell Supported Nano-Mg And The Potential Application Of Exhausied Composite As Catalyst

Artemia egg shell?Shell?is rich in chitin,and has the 3D pore structure.The pore surface carries functional groups such as-OH.At present,most of studies focus on Shell's carrier function,and ignore the multiple functions due to its unique structure and inclusions.Studies have shown that Pb²⁺could be absorbed by Shell,but it has few in-depth researchs reported that if Shell could use its unique 3D pore structure to support nano-metal oxides to enhance its efficient to absorb heavy metals and the reuse of heavy metal holders after adsorption.In the present study,Artemia egg shell was used as carrier to preparate bio-composite material loaded magnesium?Shell-Mg?,compared egg shells and bio-composite adsorbent?Shell-Mg?to research their adsorption properties and mechanisms for typical heavy metals,and processed the heavy metal holder to obtain a material with photocatalytic effect,provided a theoretical basis for the high value utilization of biological resources.The adsorption experiment of Shell for heavy metals showed:The adsorption capacity of Shell for Pb²⁺,Zn²⁺,Cu²⁺was stable when the pH values range from 2 to 5,and the pH values range for Cd²⁺from 2 to 7.The sorption capacity increased with increasing pH.the adsorption isotherms suggested that the adsorption of the four heavy metal was endothermic reaction.Different mathematical models of the adsorption kinetics and isotherms suggested that the adsorption of Shell for these four heavy metals could be controlled by multi-stage adsorption.Under the optimal conditions,Shell's adsorption capacity for these four heavy metals was 26.71 mg/g,53.51 mg/g,53.81 mg/g and 21.37mg/g respectively.In the presence of coexisting ions like Ca²⁺in solution,with the increase of Ca²⁺concentration,the adsorption capacity of Shell for heavy metal ions obviously decreased.It showed that Shell does not have selective adsorption capacity for Pb²⁺,Cd²⁺,Zn²⁺,Cu²⁺.The adsorption experiment of Shell-Mg for heavy metals showed:Under optimal conditions,the adsorption capacity of Shell-Mg was higher than that of Shell,Shell-Mg's adsorption capacity for Pb²⁺,Zn²⁺,Cu²⁺,Cd²⁺was 261.28 mg/g,243.06 mg/g,199.71mg/g and 257.64 mg/g respectively.The adsorption capacity of Shell-Mg for Pb²⁺,Zn²⁺,Cu²⁺was stable when the pH values range from 2 to 5,and the pH values range for Cd²⁺from 2 to 7.The adsorption capacity of Shell-Mg gradually increased.The quantity of the material adsorpted was increasing as the temperature rised.Different mathematical models of the adsorption kinetics and isotherms suggested that the adsorption of Shell-Mg for these four heavy metals could be controlled by multiple mechanisms.With the addition of coexisting ions,Shell-Mg was better than Shell in absorbing heavy metal ions.Compared with Shell,Shell-Mg showed better selective adsorption for Pb²⁺,Cd²⁺,Zn²⁺,Cu²⁺,Among them,the selective adsorption of Pb²⁺and Cu²⁺were the best.The adsorption results about SEM?XRD showed that Shell-Mg had better adsorption selectivity than Shell,less affected by conventional interference ions;large adsorption capacity;the immobilization of magnesium hydroxide greatly enhanced the adsorption efficient of Artemia egg shells for heavy metals.Shell-Mg-metal after adsorption was calcined at 600?,then had the function of catalytic degradation of dye wastewater under UV light,can be used as catalyst,avoided secondary pollution caused by the regeneration of the adsorbent,and achieved the high value utilization of heavy metal holder.