MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China.
MOE Key Laboratory of Resources and Environmental Systems Optimization, College of Environmental Science and Engineering, North China Electric Power University, Beijing, 102206, China.
Chemosphere. 2022 Feb;288(Pt 3):132644. doi: 10.1016/j.chemosphere.2021.132644. Epub 2021 Oct 21.
Anaerobic digestion (AD) with hydrothermal (HT) pretreatment (sequential HT-AD treatment) is a novel technology for sludge management. HT-AD sludge is rich in functional groups and its applications as pollutant sorbents might be a win-win strategy. This study investigated the removal of uranium (VI) from water using HT-AD sludge as affected by solution pH, temperature, and ion strength. The reusability and heavy metal risk of HT-AD sludge were also assessed. The batch sorption experiments demonstrated that even at an acidic initial pH of 3.2, the maximum adsorption of HT-AD sludge for uranium (VI) reached 117.13 mg/g, higher than that of most carbon-based materials. The inner-sphere and out-sphere complexation between uranium (VI) and the HT-AD sludge dominated the adsorption when pH was in the range of 2-6 and 6-11, respectively. The FTIR and XPS analysis indicated that the primary mechanisms of uranium (VI) adsorption by the HT-AD sludge were the surface complexation and the electric attraction between uranium (VI) and the functional groups (e.g. -COO-) on HT-AD sludge. The removal rate of uranium (VI) by HT-AD sludge only decreased by ∼7% after 3 consecutive adsorption cycles. Leaching experiment showed that less than 5% of the total heavy metal were released from HT-AD sludge. Our research proved that HT-AD sludge can be used as an efficient uranium (VI) adsorbent with good reusability and environmental safety.
厌氧消化（AD）与水热（HT）预处理（顺序 HT-AD 处理）是一种用于污泥管理的新型技术。HT-AD 污泥富含官能团，将其作为污染物吸附剂可能是一种双赢的策略。本研究探讨了使用 HT-AD 污泥去除水中铀（VI）的情况，受溶液 pH 值、温度和离子强度的影响。还评估了 HT-AD 污泥的可重复使用性和重金属风险。批量吸附实验表明，即使在初始 pH 值为 3.2 的酸性条件下，HT-AD 污泥对铀（VI）的最大吸附量也达到了 117.13mg/g，高于大多数基于碳的材料。当 pH 值在 2-6 和 6-11 范围内时，铀（VI）与 HT-AD 污泥之间的内球和外球络合分别主导了吸附。FTIR 和 XPS 分析表明，HT-AD 污泥吸附铀（VI）的主要机制是表面络合和铀（VI）与 HT-AD 污泥上的官能团（例如-COO-）之间的静电引力。HT-AD 污泥的铀（VI）去除率在连续 3 次吸附循环后仅下降了约 7%。浸出实验表明，HT-AD 污泥中释放的总重金属不到 5%。我们的研究证明，HT-AD 污泥可用作高效的铀（VI）吸附剂，具有良好的可重复使用性和环境安全性。
