Department of Civil and Environmental Engineering, University of California, Irvine, 92697, United States; Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
Department of Civil and Environmental Engineering, University of California, Irvine, 92697, United States.
Sci Total Environ. 2024 Aug 10;937:173370. doi: 10.1016/j.scitotenv.2024.173370. Epub 2024 May 19.
To innovate the design of water treatment technology for algal toxin removal, this research investigated the mechanisms of cyanotoxin microcystin-LR (MC-LR) removal by a coupled adsorption-biodegradation. Eight types of woody carbonaceous adsorbents with and without Sphingopyxis sp. m6, a MC-LR degrading bacterium, were tested for MC-LR removal in water. All adsorbents showed good adsorption capability, removing 40 % to almost 100 % of the MC-LR (4.5 mg/L) within 48 h in batch experiments. Adding Sphingopyxis sp. m6 continuously promoted MC-LR biological removal, and successfully broke the barrier of adsorption capacity of tested adsorbents, removing >90 % of the MC-LR in most of the coupled adsorption-biodegradation tests, especially for those adsorbents had low physiochemical adsorption capacity. Variance partitioning analysis indicated that mesopore was the dominant contributor to adsorption capacity of MC-LR in pure adsorption treatments, which acted synergistically with electrical conductivity, polarity and total functional groups on the absorbent. Pore structure was the key factor beneficial for the growth of Sphingopyxis sp. m6 (51% contribution) and subsequent MC-LR biological removal rate (80 % contribution). Overall, pinewood-based carbonaceous adsorbents (especially pinewood activated carbon) exhibited the highest adsorption capacity towards MC-LR and provided the most favorable conditions for biological removal of MC-LR, largely because of their high mesopore volume, total functional groups and electric conductivity. The research outcomes not only deepened the quantitative understanding of mechanisms for MC-LR removal by the coupled process, but also provided theoretical basis for future materials' selection and modification during the practical application of coupled process.
为了创新水处理技术以去除藻毒素，本研究调查了通过耦合吸附-生物降解去除微囊藻毒素 LR（MC-LR）的机制。测试了 8 种带有和不带有 MC-LR 降解菌 Sphingopyxis sp. m6 的木质碳质吸附剂，用于水中 MC-LR 的去除。在批处理实验中，所有吸附剂在 48 小时内均表现出良好的吸附能力，去除了 40%至近 100%的 MC-LR（4.5mg/L）。连续添加 Sphingopyxis sp. m6 可促进 MC-LR 的生物去除，并成功打破了测试吸附剂吸附容量的瓶颈，在大多数耦合吸附-生物降解测试中去除了>90%的 MC-LR，尤其是对那些物理化学吸附容量较低的吸附剂。方差分解分析表明，介孔是纯吸附处理中 MC-LR 吸附容量的主要贡献者，与吸附剂的电导率、极性和总官能团协同作用。孔结构是有利于 Sphingopyxis sp. m6 生长（贡献 51%）和随后 MC-LR 生物去除率（贡献 80%）的关键因素。总体而言，基于松木的碳质吸附剂（尤其是松木活性炭）对 MC-LR 表现出最高的吸附能力，并为 MC-LR 的生物去除提供了最有利的条件，这主要是因为它们具有较高的介孔体积、总官能团和电导率。研究结果不仅深化了对耦合过程去除 MC-LR 机制的定量理解，而且为未来实际应用中耦合过程中材料选择和改性提供了理论依据。
