Photoassisted Degradation of 4-Chlorophenol and p-Cresol Using MgAl Hydrotalcites

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• 作者：Angeles Mantilla ; Gabriela Ja虂come-Acatitla ; Getsemani虂 Morales-Mendoza ; Francisco Tzompantzi ; Ricardo Go虂mez
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2011
• 出版时间：March 2, 2011
• 年：2011
• 卷：50
• 期：5
• 页码：2762-2767
• 全文大小：889K
• 年卷期：v.50,no.5(March 2, 2011)
• ISSN：1520-5045

文摘

MgAl hydrotalcites, or layered double hydroxides (LDHs), with different Mg/Al molar ratios were synthesized by the coprecipitation method. The structure of the solids was collapsed by thermal treatment at 723 K obtaining MgAl mixed oxides with high specific surface areas (264鈭?18 m²/g). When these oxides were put in contact with aqueous solutions containing 4-chlorophenol and para-cresol (80 ppm:0.62 and 0.73 mmol, respectively) the layered structure was recovered by rehydration of the material showing the named 鈥渕emory effect鈥?of LDH materials. Mg/Al LDHs were active for chlorophenol and p-cresol degradation under UV irradiation, being more active and selective to the mineralization of the pollutants than TiO₂ P-25 photocatalysts. Since Mg/Al hydrotalcites are not semiconductors their high photoassisted activity was surprising; this activity was explained by a photo excitation which produces mobility of charges in the lamellar structure, inducing the formation of photoactive defects.