Preparation Of Activated Carbon Supported Calcium Silicate And Its Adsorption Behavior For Heavy Metal-organics Compound Pollutants

With the rapid development of industrial production,the pollution components in water bodies are becoming more and more complex,and interactions between components play a more and more important role in the formation of combined pollution,which makes the treatment of wastewater more difficult.Compared with the traditional processing method,adsorption method is simple and easy,low processing cost and is suitable for processing all kinds of wastewater,and the choice of a high performance and excellent adsorption agent is the key to using this method to achieve good treatment effect and economic benefit.Herein,the activated carbon?AC??calcium nitrate and sodium silicate were used as raw materials to synthesis the activated carbon supported calcium silicate?CS/AC?with different ratios through changing the quality of AC.The adsorption properties of different proportion of composite materials for heavy metal and dye molecules combined pollutants were investigated and compared with mesoporous calcium sulphate?CS?and activated carbon.The adsorption properties and adsorption mechanism of composite materials on various complex pollutants were systematically investigated.?1?Using activated carbon,calcium nitrate tetrahydrate,and sodium hydrate sodium hydrate as raw materials,activated carbon loaded with different ratios?1:1,1:2.5,1:4,1:7,1:10?of calcium silicate were prepared.The composites were characterized by infrared spectroscopy,X-ray diffraction,scanning electron microscopy,transmission electron microscopy,energy spectrum and BET surface analysis to characterize their morphology,structure and composition.The results showed that although no template was added during the preparation of the composite material,the calcium silicate loaded on the activated carbon had the same flower-like morphology as that of the previously synthesized calcium mesoporous silicate.The pores were abundant.The results of BET analysis showed that the larger the proportion of calcium silicate in the composite,the smaller the specific surface area,and the smallest specific surface area of CS/AC?1:1?was 490.21 m²/g,the largest specific surface area of CS/AC?1:10?is 829.47 m²/g.?2?Adsorption of Cu²⁺,Zn²⁺and methyl orange?MO?solution and Cu²⁺-Zn²⁺-MO simulated compound pollution solution of each adsorbent were investigated by using the above composite materials as adsorbents.The results show that the larger the proportion of CS in the composite CS/AC,the better the adsorption effect on heavy metal ions,the worse the adsorption effect on the dye molecules,indicating that increasing the loading of CS can effectively improve the effect of composite materials on heavy metal ions;Compared with single-component solution and mixed solution,CS/AC adsorption amount of heavy metal ions in mixed solution is smaller than that of single heavy metal ions,while adsorption amount of MO is increased,indicating that MO in the mixed solution inhibition of heavy metal adsorption,while the presence of heavy metal ions can promote MO adsorption.?3?Mesoporous calcium silicate,activated carbon and CS/AC?1:4?were used as adsorbents,and the adsorption effect of the amounts of three adsorbents for Cu²⁺-MO?Cu²⁺-MB?Zn²⁺-MO?Zn²⁺-MB?Cd²⁺-MO and Cd²⁺-MB simulated complex pollution solution were investigated respectively,and compared the adsorption capacity of the three adsorbents.The results show that calcium silicate can effectively adsorb heavy metal ions in the mixed solution,but the removal ability of the dye molecules is not good;the activated carbon has a good adsorption effect on the dye molecules in the mixed solution,but the removal ability of the heavy metal ions is insufficient;however,the composite materials show good adsorption capacity for all the components in the mixed solution,so it is expected to have a great development in the treatment of compound pollution.?4?Using CS/AC?1:4?as adsorbent,the effects of adsorbent dosage,adsorption temperature and adsorption time on the adsorption performance of Cu²⁺-MO?Cu²⁺-MB?Zn²⁺-MO?Cd²⁺-MO?Cd²⁺-MB?Pb²⁺-MO and Pb²⁺-MB simulated pollution solution were systematically investigated.The results showed that with the increase of adsorbent dosage,the adsorption rate of each component in the mixed solution increased continuously.The dye molecule was completely adsorbed at about 25 and 35 mg,and the adsorption rate of heavy metal ions was Pb²⁺>Cu²⁺>Cd²⁺>Zn²⁺.With the increase of temperature,the adsorption amount of each component in the mixed solution will have the opposite change,some change trends are consistent,and some changes in temperature are not obvious.Using Langmuir,Freundlich,Redlich-Peterson,and Temkin four isothermal adsorption models to fit the experimental data,the results are not all the same.It shows that the interaction between different kinds of heavy metal ions and dye molecules is different,and the adsorption process is complicated.The results of kinetic studies showed that the CS/AC adsorbed the mixed solution rapidly,and the adsorption equilibrium was reached when the time was about 100min.The adsorption process conformed to the quasi-secondary adsorption model.This paper focuses on the composite materials for heavy metal-organics compound pollutants adsorption properties for the practical application of the material provides a large number of data is a great value for the development of a new type of adsorbent.