Department of Chemistry, National Institute of Technology, Hamirpur, HP, 177005, India.
Department of Chemistry, National Institute of Technology, Hamirpur, HP, 177005, India.
Environ Res. 2022 Sep;212(Pt C):113328. doi: 10.1016/j.envres.2022.113328. Epub 2022 Apr 26.
Green synthesis of nanomaterials is a sustainable, biologically safe, reliable, and eco-friendly approach. Green synthesis is beneficial to reduce the devastating effects of the traditional chemical synthesis methods and particularly aims at decreasing the usage of toxic chemicals. This review deals with the green synthesis of silica nanoparticles (SiO NPs) with emphasis on the engineering surface properties for enhanced adsorption capability and their applications as novel nano-adsorbents for water pollutants removal. Green synthesized SiO NPs have shown excellent adsorption properties with higher adsorption capacity of 150-200 mg/g and more than 95% removal for various toxic water pollutants along with reusability for more than 5 cycles. These SiO NPs show fascinating physical and chemical properties i.e. tunable size (5 nm to more than 100 nm), low toxicity, biocompatibility, high porosity, higher specific surface area (500--700 m/g) making them attractive/suitable for several applications in biomedical, agriculture, catalysis, construction, water treatment, etc. Commonly, highly pure SiO NPs are synthesized from organic chemicals (very expensive and highly toxic in nature) as a precursor that led to high production costs, high energy consumption, and environmental hazards. On the other hand, green synthesis of SiO NPs from natural resources like biomass that includes rice husk, bamboo leaves/stem, sugarcane bagasse, corn cobs, wheat straw, etc. is cost-effective, less toxic, and eco-friendly which has been discussed in detail. Furthermore, the effect of key synthesis parameters (i.e., temperature, time, concentration, pH, etc.) on the morphology, size, purity, and specific surface area of SiO NPs have been summarized. Finally, the applications of SiO NPs as nano-adsorbents for the removal of toxic water pollutants (i.e., heavy metal cations, anions, dyes, etc.) including the adsorption mechanisms along with the future scope, challenges, and suggestions have been discussed.
绿色合成纳米材料是一种可持续、生物安全、可靠和环保的方法。绿色合成有利于减少传统化学合成方法的破坏性影响，特别是旨在减少有毒化学物质的使用。本综述涉及使用绿色合成方法合成二氧化硅纳米颗粒（SiO NPs），重点介绍了工程表面特性，以提高吸附能力，并将其作为新型纳米吸附剂应用于去除水中污染物。绿色合成的 SiO NPs 表现出优异的吸附性能，对各种有毒水污染物的吸附容量高达 150-200 mg/g，去除率超过 95%，并且可以重复使用 5 次以上。这些 SiO NPs 表现出迷人的物理和化学特性，例如可调尺寸（5nm 至 100nm 以上）、低毒性、生物相容性、高孔隙率、更高的比表面积（500-700 m/g），使它们在生物医学、农业、催化、建筑、水处理等领域具有吸引力/适用性。通常，高纯 SiO NPs 是由有机化学品（性质非常昂贵且毒性很高）作为前体制备的，这导致生产成本高、能耗高和环境危害。另一方面，从生物质等自然资源（如稻壳、竹叶/茎、甘蔗渣、玉米芯、麦秸等）绿色合成 SiO NPs 具有成本效益高、毒性低、环保等优点，这一点已在文中详细讨论。此外，还总结了关键合成参数（如温度、时间、浓度、pH 等）对 SiO NPs 的形态、尺寸、纯度和比表面积的影响。最后，讨论了 SiO NPs 作为纳米吸附剂去除有毒水污染物（如重金属阳离子、阴离子、染料等）的应用，包括吸附机制以及未来的范围、挑战和建议。
