Characterization and evaluation of factors influencing microcystin-LR removal by granular activated carbon produced from different raw materials

ABSTRACT Microcystins (MC), which are among the cyanotoxins more commonly found in cyanobacterial blooms, are not efficiently removed by full-cycle water treatment technologies. As an additional barrier, there is the adsorption process with granular activated carbon (GAC). This research compared the efficiency of MC-LR removal by seven GACs produced from different raw materials, analyzing these samples’ properties: moisture, ash content, pH and textural characteristics. Initially, the results indicated that the GAC properties were influenced by the source material, as well as by the production method. In the adsorption assays, the Langmuir model indicated that in 4h, with 100 mg.L-1 dosage, the granular activated carbon of lignite (CGLIN) had the highest MC-LR (Co: 115.1 µg.L-1) removal capacity (97.2%), with qe,max of 10.6 mg.g-1. The volume of mesopores significantly influenced the adsorption capacity of microcystin by the evaluated GACs (r=0.98, Pearson). These results can support the application of the MC-LR adsorption process in water treatment plants to minimize intoxication with contaminated water.

摘要：微囊藻毒素（Microcystins, MC）是蓝藻水华中最为常见的蓝藻毒素之一，无法通过全流程水处理技术实现有效去除。颗粒活性炭（granular activated carbon, GAC）吸附工艺可作为补充净化屏障。本研究针对7种不同原料制备的颗粒活性炭，对比其对微囊藻毒素-LR（MC-LR）的去除效能，并对样品的含水率、灰分含量、pH值及孔隙结构特征展开分析。初步结果表明，颗粒活性炭的性能同时受原料来源与制备工艺的影响。吸附实验中，基于朗缪尔模型的分析结果显示：在吸附时长4h、投加量为100 mg·L⁻¹的条件下，褐煤基颗粒活性炭（CGLIN）对初始浓度为115.1 μg·L⁻¹的MC-LR去除率最高，可达97.2%，最大吸附容量（qe,max）为10.6 mg·g⁻¹。介孔体积对本次评估的颗粒活性炭的微囊藻毒素吸附容量具有显著影响（皮尔逊（Pearson）相关系数r=0.98）。本研究结果可为水处理厂应用MC-LR吸附工艺，降低受污染水体引发的中毒风险提供技术支撑。