| LDHs belongs to layer material, which have larger specific surface area and high anion adsorption capacity, and the calcined LDHs can generated mixed metal oxides which have the characteristic of "memory effect". It performance a better adsorption capacity compare with uncalcined LDHs. LDHs have the advantage of easy synthesis and low cost and have been widely researched by using as high phosphorus adsorbent in the wastetreatment.Using hydrothermal method synthesized three kinds of LDHs including Zn-Al-LDHs, Friedel-LDHs and Ca-Al-LDHs. After calcined under 350℃, the three kinds of LDHs were generated mixed metal oxides (LDO) mark CLDHs. LDHs and CLDHs were tested by XRD, SEM, FT-IR, TG-DTA to characterize crystallinity, morphology and analysis functional group, thermal stability ability. Test adsorption ability of LDHs and CLDHs to phosphate adsrobate, then investigate the influence factor of adsorption process, including adsorbent dosage, initial anion concentration, initial pH value, time and temperature. Discuss adsorption kinetics study and adsorption isotherm curve of CLDHs on phosphorus adsorption, preliminary analysis the adsorption mechanism. Respectly, three kinds of CLDH have certain adsorption effect on phosphate. Adsorption capacity can order by: Friedel-LDHs >Zn-Al-LDHs>Ca-Al-LDHs. According to the adsorption result, the maximum adsorption of Ca-Al-LDOs was 11.44mg/g, failed to reach our respect. So we compare isothremal fitting of Friedel-LDOs and Zn-Al-LDOs, which indicate that two fitting result are better agree with Langmuir model, accroding to the result, the maximun phosphate adsorption is 225.22mg/g and 124.89mg/g respectively, which show a high adsorpting ability; and kinetics fitting result are both better agree with pseudo second order model. |
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