Synthesis and Characterization of Antibacterial Silver Nanoparticle-Impregnated Rice Husks and Rice Husk Ash

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• 作者：Di He ; Atsushi Ikeda-Ohno ; Daniel D. Boland ; T. David Waite
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：May 21, 2013
• 年：2013
• 卷：47
• 期：10
• 页码：5276-5284
• 全文大小：426K
• 年卷期：v.47,no.10(May 21, 2013)
• ISSN：1520-5851

文摘

Silver nanoparticle (AgNP)-impregnated rice husks/rice hush ash (RHs/RHA) were successfully synthesized, and their potential application as antibacterial materials in water disinfection was investigated with particular attention given to the use of both white rice husk ash (WRHA) and black rice husk ash (BRHA) produced by the combustion of RHs as AgNP supports. AgNPs, with diameter of 20 nm, were anchored tightly onto RHA, with the emplacement of the AgNPs on these supports increasing the antibacterial activity of the AgNPs through diminution in the extent of nanoparticle aggregation. Ag K-edge XANES analysis revealed that AgNP-impregnated RHs/RHA are composed of both Ag(0) and Ag(I) species with the Ag(I)/Ag(0) ratio following the order WRHA (65:35) > RHs (59:41) > BRHA (7:93). Sodium thioglycolate, a strong Ag(I) ligand, significantly affected the bactericidal activities of AgNP-impregnated RHs/RHA, suggesting that Ag(I) released from AgNP-impregnated RHs/RHA plays an important role in disinfection. The rate constants of oxidative and dissociative dissolution of Ag(0) and Ag(I) species associated with BRHA are 5.0 脳 10^鈥? M^鈥?s^鈥? and 1.0 脳 10^鈥? s^鈥?, respectively, while those associated with WRHA are 7.0 脳 10^鈥? M^鈥?s^鈥? and 2.0 脳 10^鈥? s^鈥? respectively, demonstrating that the rate of dissolution of silver associated with BRHA is particularly slow. As such, the bactericidal 鈥渓ifetime鈥?of this material is long and exhibits a lower health risk as a result of release of Ag(I) to consumers than does AgNP-impregnated WRHA.