Chakma Soumik, Hasan Mehedi, Hu Yulin, Rakshit Sudip K, Kang Kang
Biorefining Research Institute (BRI) and Department of Chemical Engineering, Lakehead University, Thunder Bay, ON P7B 5E1, Canada.
Faculty of Sustainable Design Engineering, University of Prince Edward Island, Charlottetown, PE C1A 4P3, Canada.
Waste Manag. 2025 Aug 1;204:114970. doi: 10.1016/j.wasman.2025.114970. Epub 2025 Jun 26.
Heavy metal contamination of water remains a critical environmental challenge, demanding efficient, low-cost, and sustainable treatment technologies. This study presents an innovative strategy to address both wastewater pollution and industrial waste disposal by converting red mud (RM), a hazardous byproduct of aluminum production, and maple wood (MW) biomass into magnetic biochar (MBC) adsorbents. Unlike traditional post-pyrolysis biochar (BC) activation methods, a novel pre-pyrolysis biomass chemical activation approach was employed using acid (HNO) and base (KOH) to tailor the surface properties of the biomass-RM mixture prior to co-pyrolysis. The resulting materials, HNO-MBC and KOH-MBC, displayed distinct physicochemical characteristics and adsorption behaviors. Despite having a lower surface area, KOH-MBC exhibited superior removal efficiencies (∼100 %) for Cu and Pb due to its abundant oxygen-containing functional groups (-OH, -COOH). HNO-MBC achieved slightly lower removal (∼95 %) but offered higher mesoporosity. Adsorption was governed by chemisorption mechanisms, including electrostatic attraction, ion exchange, complexation, precipitation, and redox reactions, with both materials fitting pseudo-second-order kinetics and Langmuir isotherm models. Economic analysis highlighted the cost advantage of KOH-MBC (CAD 15.47/kg) over HNO-MBC (CAD 41.29/kg), reinforcing its potential for scalable environmental applications. Overall, this work offers a sustainable and cost-effective pathway to transform industrial wastes into high-performance adsorbents for heavy metal remediation in water.
水体中的重金属污染仍然是一项严峻的环境挑战，需要高效、低成本且可持续的处理技术。本研究提出了一种创新策略，通过将铝生产过程中的有害副产品赤泥（RM）和枫木（MW）生物质转化为磁性生物炭（MBC）吸附剂，来解决废水污染和工业废物处理问题。与传统的热解后生物炭（BC）活化方法不同，本研究采用了一种新颖的热解前生物质化学活化方法，使用酸（HNO）和碱（KOH）在共热解之前调整生物质-RM混合物的表面性质。所得材料HNO-MBC和KOH-MBC表现出不同的物理化学特性和吸附行为。尽管KOH-MBC的表面积较低，但由于其含有丰富的含氧官能团（-OH、-COOH），对Cu和Pb的去除效率较高（约100%）。HNO-MBC的去除率略低（约95%），但具有更高的介孔率。吸附受化学吸附机制控制，包括静电吸引、离子交换、络合、沉淀和氧化还原反应，两种材料均符合准二级动力学和朗缪尔等温线模型。经济分析突出了KOH-MBC（15.47加元/千克）相对于HNO-MBC（41.29加元/千克）的成本优势，增强了其在可扩展环境应用中的潜力。总体而言，这项工作提供了一条可持续且经济高效的途径，将工业废物转化为用于水体中重金属修复的高性能吸附剂。
