Akhil K, Chandran Preethy, Sudheer Khan S
Department of Chemistry & Biosciences, Srinivasa Ramanujan Centre, SASTRA University, Kumbakonam 612001, Tamil Nadu, India.
CeNTAB, School of Chemical and Biotechnology, SASTRA University, Thanjavur 613401, Tamil Nadu, India.
J Photochem Photobiol B. 2015 Dec;153:289-95. doi: 10.1016/j.jphotobiol.2015.10.007. Epub 2015 Oct 22.
The present study investigated the stability of zinc oxide nanoparticles (ZnO NPs) by the adsorption of humic acid (HA) and the mechanism of adsorption. The effect of humic acid on NP toxicity was determined by Escherichia coli (ATCC 13534), E. coli (ATCC 25922), and Pseudomonas putida (MTCC 4910). The nanoparticles showed low zeta potential and were least stable in the absence of HA. However, the negative surface charge of the particles increased in the presence of HA (0-50mg/L) that reduced the propensity of nanoparticles to aggregate in water. A decrease in absorbance of ZnO NPs at 375 nm (plasmon peak) was noted in the presence of HA by UV-visible spectrophotometric analysis. A blue shift towards 370 nm was noted when the concentration of HA was above 20mg/L. The HA adsorbed ZnO NPs showed higher zeta potential (>-30 mV) and were highly stable. HA reduced the photocatalytic activity of ZnO and at the same time increased the photostability of ZnO.
本研究通过腐殖酸（HA）的吸附作用研究了氧化锌纳米颗粒（ZnO NPs）的稳定性及其吸附机制。通过大肠杆菌（ATCC 13534）、大肠杆菌（ATCC 25922）和恶臭假单胞菌（MTCC 4910）测定了腐殖酸对纳米颗粒毒性的影响。纳米颗粒显示出低ζ电位，在没有HA的情况下最不稳定。然而，在存在HA（0-50mg/L）的情况下，颗粒的负表面电荷增加，这降低了纳米颗粒在水中聚集的倾向。通过紫外可见分光光度分析发现在存在HA的情况下，ZnO NPs在375nm（等离子体峰）处的吸光度降低。当HA浓度高于20mg/L时，观察到向370nm的蓝移。吸附了HA的ZnO NPs显示出更高的ζ电位（>-30 mV）且高度稳定。HA降低了ZnO的光催化活性，同时提高了ZnO的光稳定性。
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