Preparation Of Heavy Metal Adsorbent Materials And Its Application In Aquatic Products By-products

In recent years,with the increasing demand for aquatic products,requirement for safety tare increasing is becoming more strict.Due to the bio-accumulation of heavy metals and the potential harm to the human body,heavy metal removal technology is practically significant.Removal of heavy metals from aquatic products has been drawn attention by researchers.In this paper,removal of heavy metals by several adsorbents materials was studied,the aim was to screen out an adsorbent which had the best effect on heavy metal removal and the least loss of nutrients.This result will provide a new method for the removal of heavy metals in by-products of aquatic products,and provide a theoretical basis for comprehensive utilization of by-products of aquatic products.The results were as follows:(1)Shell-based hydroxyapatite was prepared.The effect of heavy metal removal on hydroxyapatite,shell powder,D401 and D402 chelating resin was studied.The results showed that the best adsorption effect of heavy metals was at pH 7.The equilibrium time(60 min)of hydroxyapatite and shell powder for heavy metals adsorption was shorter than the commercial resin.Shell-based hydroxyapatite had the highest adsorption capacity for four heavy metals,and the equilibrium adsorption capacity of lead,chromium,cadmium and copper was 20.0,2.5,9.5 and 7.5 mg/g,respectively.The deduction rates of lead,chromium,cadmium and copper ions were 109.88%,51.68%,76.02% and 52.17%,respectively.The removal efficiency of lead,chromium,cadmium and copper ions was 109.88%,51.68%,76.02% and 52.17% respectively,by using hydroxyapatite to remove heavy metals from by-products of aquatic products.However,polysaccharides and other nutrients in the by-products were lost greatly.(2)The three different functional group-modified SBA-15-mesoporous materials(MT-SBA-15,MBT-SBA-15 and APDC-SBA-15,)were prepared,and were characterized by Fourier transform infrared spectroscopy(FTIR),Differential scanning calorimeter(DSC),X-ray diffraction(XRD),and Nitrogen adsorption.The results showed that the adsorption capacity of the three mesoporous materials for Pb,Cr,Cd and Cu was higher than that of hydroxyapatite,and the adsorption capacity of APDC-SBA-15 was the highest,when the concentration of metal ions reached 1200mg/L,the maximum adsorption capacities of Pb,Cr,Cd and Cu were 223.6,240.0,259.8 and 259.0mg/g,respectively.Using three mesoporous materials for removing spiked lead ion from cooking liquor of Ruditapes philippinarum,the removal rate of spiked lead ion was 73% ~ 80%,and the loss of polysaccharide was 6.07% ~ 7.32%.When the removal of heavy metal ions in the polysaccharide cooking liquor of Ruditapes philippinarum by,the removal rate of APDC-SBA-15 materials for lead was the highest among the three materials(84.50%),and the loss rate of polysaccharide was the lowest(2.57%).In removal of heavy metal ions in oysters polypeptide,the removal rate of lead ions by APDC-SBA-15 material was reduced(62.2%),and a higher loss rate of protein was found(14.62%).(3)Diol-APDC-SBA-15 materials were made by modifying the outer surface of APDC-SBA-15 materials,and were characterized by FTIR,DSC,XRD,and Nitrogen adsorption.The result showed that after an outer surface modification,a higher capacity for removal of heavy metal ions was still retained,but was slightly lower.The removal effect of APDC-SBA-15 materials on heavy metal in the polysaccharide of Ruditapes philippinarum was lower than that of Diol-APDC-SBA-15 materials,and the nutrition loss rate increased slightly.The removal rate of lead ions in the oyster polypeptide was 77% by Diol-APDC-SBA-15 material,and the removal rate of the protein was 1.22%.Based on the above results,the four kinds of mesoporous materials for the removal of heavy metal possess the performance of fast,efficient,large and environmentally friendly.APDC-SBA-15 materials are suitable for application in the retention of polysaccharide components,and Diol-APDC-SBA-15 materials are good for retention of aquatic protein fraction during heavy metal removal of aquatic product.