College of Architecture and Environment, Sichuan University, Chengdu, 610065, China.
Institute for Disaster Management and Reconstruction, Sichuan University-The Hong Kong Polytechnic University, Chengdu 610065, China.
Int J Biol Macromol. 2024 Jan;255:127534. doi: 10.1016/j.ijbiomac.2023.127534. Epub 2023 Oct 20.
The objective of this work is utilizing fly ash to synthesize tobermorite (TOB) with a higher specific surface area and layered structure, and incorporating it into the starch/acrylic acid network to boost the drought resistance, water retention and heavy metal adsorption properties. The water absorption and water retention performance and cadmium adsorption characteristics of tobermorite/leftover rice-based composite hydrogel (TOB@LR-CH) were evaluated by water absorption swelling test, soil evaporation test and batch adsorption experiment. By adjusting the addition of TOB and other synthesized conditions, the swelling property (from 114.80 g/g to 322.64 g/g), water retention (71.80 %, 144 h) and Cd adsorption characteristics (up to 591.36 mg/g) were significantly enhanced. Adding a moderate amount of TOB (2 wt%) provided the most uniform tobermorite dispersion during synthesis, and TOB2@LR-CH exhibited the most stable three-dimensional network and highest proportion of effective TOB. The adsorption behavior of cadmium on TOB2@LR-CH was more consistent with the pseudo-second-order kinetics and Langmuir isotherm models. Additionally, the regeneration test results displayed that the adsorption removal rate of cadmium by TOB2@LR-CH adsorbent remained stable after 5 cycles. This study demonstrates that TOB@LR-CH has good water absorption and water retention potential in arid and semi-arid soils, and also has potential application prospects in remediating Cd(II)-contaminated soil.
本工作旨在利用粉煤灰合成具有更高比表面积和层状结构的托贝莫来石（TOB），并将其掺入淀粉/丙烯酸网络中，以提高干旱抗性、保水和重金属吸附性能。通过吸水膨胀试验、土壤蒸发试验和批量吸附试验，评价了托贝莫来石/剩余稻基复合水凝胶（TOB@LR-CH）的吸水和保水性能以及镉吸附特性。通过调整 TOB 的添加量和其他合成条件，可显著提高膨胀性能（从 114.80 g/g 到 322.64 g/g）、保水性能（71.80%，144 h）和 Cd 吸附特性（高达 591.36 mg/g）。添加适量的 TOB（2wt%）在合成过程中提供了最均匀的托贝莫来石分散性，而 TOB2@LR-CH 表现出最稳定的三维网络和最高比例的有效 TOB。Cd 在 TOB2@LR-CH 上的吸附行为更符合准二级动力学和 Langmuir 等温模型。此外，再生试验结果表明，TOB2@LR-CH 吸附剂对镉的吸附去除率在 5 次循环后保持稳定。本研究表明，TOB@LR-CH 在干旱和半干旱土壤中具有良好的吸水和保水潜力，并且在修复 Cd(II)污染土壤方面也具有潜在的应用前景。
