School of Engineering, RMIT University, Melbourne, VIC, 3001, Australia.
School of Engineering, RMIT University, Melbourne, VIC, 3001, Australia.
Chemosphere. 2022 Mar;291(Pt 3):132760. doi: 10.1016/j.chemosphere.2021.132760. Epub 2021 Nov 2.
Major agricultural solid waste, rice husk (RH)-based mesoporous materials were prepared by potassium hydroxide (KOH) treatment of RH and RH hydrochar (RHH) produced at 180 °C with 20 min reaction time. In this study, RH was treated with three different methods: RH activation by KOH (KOH-RH), RH activation by KOH-aqueous silver (Ag)-shell nanoparticle (AgNP) incorporation followed calcination at 550 °C for 2 h (AgNP-KOH-RH) and hydrothermally carbonized RH activation by KOH (KOH-RHH). The main objective of this study was to determine the effect of KOH activation with different synthesis approaches and compare the characterization results of RH based porous material to identify the potential adsorbent application for wastewater treatment. Therefore, after activation in different methods, all interactive properties such as elemental, chemical, structural, morphological, and thermal analyses were investigated comprehensively for all samples. The crystallinity peak intensity around 22°λ at the angle of diffraction of 2θ confirmed the presence of silica, higher stability of the material, and removal of organic components during the KOH activation. AgNP-KOH-RH and KOH-RHH presented high porosity on the outer surface. The presence of negligible volatile matter in KOH-RHH by TGA demonstrated the decomposition of organic compound. Very high ratio of aromatic carbon and lignin content by FTIR and XPS analysis in both AgNP-KOH-RH and KOH-RHH showed these two samples have improved stability. Very high negative surface charge (zeta potential) in AgNP-KOH-RH (-43.9 mV) and KOH-RHH (-43.1 mV) indicated the enhanced water holding capacity. Surface area for all experimented porous materials has been enhanced after KOH activation, where KOH-RHH demonstrated the maximum surface area value, 27.87 m/g. However, AgNP-KOH-RH presented maximum pore diameter, 18.16 nm, and pore volume, 0.12 cm/g. Hence, it can be concluded that both KOH-RHH and AgNP-KOH-RH have the potential to be implemented as wastewater adsorbents.
主要的农业固体废物稻壳（RH）通过在 180°C 下反应 20 分钟用氢氧化钾（KOH）处理 RH 和 RH 水热炭（RHH）制备介孔材料。在这项研究中，RH 通过三种不同的方法进行处理：用 KOH 处理 RH（KOH-RH）、用 KOH-载银（Ag）纳米壳颗粒（AgNP）处理 RH 然后在 550°C 下煅烧 2 小时（AgNP-KOH-RH）和用 KOH 水热碳化 RH 处理 RH（KOH-RHH）。本研究的主要目的是确定不同合成方法的 KOH 活化的影响，并比较 RH 基多孔材料的表征结果，以确定其在废水处理中的潜在吸附剂应用。因此，在不同方法活化后，全面研究了所有样品的元素、化学、结构、形态和热分析等所有相互作用性质。在 2θ 角的衍射角度，大约 22°λ 的结晶度峰值强度证实了硅的存在、材料的更高稳定性以及在 KOH 活化过程中有机成分的去除。AgNP-KOH-RH 和 KOH-RHH 在外壳表面具有高的多孔性。TGA 证明 KOH-RHH 中挥发性物质的含量可忽略不计，表明有机化合物的分解。FTIR 和 XPS 分析表明，AgNP-KOH-RH 和 KOH-RHH 中芳族碳和木质素含量非常高，表明这两种样品的稳定性得到了提高。AgNP-KOH-RH（-43.9 mV）和 KOH-RHH（-43.1 mV）的非常高的负表面电荷（zeta 电位）表明了增强的持水能力。经过 KOH 活化后，所有实验多孔材料的表面积都得到了提高，其中 KOH-RHH 表现出最大的表面积值 27.87 m/g。然而，AgNP-KOH-RH 表现出最大的孔径 18.16nm 和孔体积 0.12cm/g。因此，可以得出结论，KOH-RHH 和 AgNP-KOH-RH 都有可能作为废水吸附剂使用。
