Sequestration, recovery, and reuse of cationic, anionic, and non-ionic dyes using bentonite

IF 5.8 3区环境科学与生态学 0 ENVIRONMENTAL SCIENCES

Environmental Science and Pollution Research Pub Date : 2025-09-10 DOI:10.1007/s11356-025-36929-9

Foysal Ahmed Nobel, Robiul Islam Fahim, Rakibul Hassan, Sultana Bedoura

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Abstract

This study quantitatively evaluated the adsorption performance of natural bentonite for removing three dye classes—cationic (Basic dye: BEZACRYL RED GRL), anionic (Reactive dye: AVITERA LIGHT RED SE), and non-ionic (Disperse dye: BEMACRON BLUE HP3R) from synthetic textile wastewater. Batch adsorption experiments were conducted under varying conditions of contact time (15–90 min), adsorbent dosage (20–60 g L⁻¹), pH (4 and 12), and temperature (25–100 °C), with dye concentrations quantified by UV–Vis spectroscopy. At a contact time of 30 min and room temperature (25 °C), maximum removal efficiencies reached 99.98% and 99.93% for cationic dye, 65.26% and 77.13% for anionic dye, and 94.04% and 79.40% for non-ionic dye at pH 4 and pH 12, respectively. For non-ionic dyes, the removal efficiency improved slightly at elevated temperature (nearly at 60 °C). Kinetic analysis showed that cationic dye adsorption followed the pseudo-second-order (PSO) model (R² = 0.9999), indicating a chemisorption mechanism driven by electrostatic interactions with negatively charged bentonite basal planes. Non-ionic dye adsorption fitted better to the pseudo-first-order (PFO) model (R² = 0.9821), consistent with physisorption via van der Waals forces and hydrogen bonding. Anionic dye adsorption showed poor fits to both models (R² < 0.60), reflecting weak uptake due to electrostatic repulsion from the negatively charged bentonite surface. Equilibrium data were best described by the Langmuir isotherm, suggesting monolayer adsorption with maximum capacities of 0.486, 0.373, and 0.483 mg g⁻¹ for cationic, anionic, and non-ionic dyes, respectively. Recovered dyes were reused in textile printing, producing stable and vibrant prints for cationic and non-ionic dyes, with slightly reduced intensity for anionic dyes. This work demonstrates bentonite’s dual role as an efficient, low-cost adsorbent and a means for resource recovery, providing novel insights into simultaneous wastewater treatment and dye reuse across multiple dye classes.

Graphical abstract

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利用膨润土对阳离子、阴离子和非离子染料进行隔离、回收和再利用。

本研究定量评价了天然膨润土对合成纺织废水中阳离子染料（碱性染料：BEZACRYL RED GRL）、阴离子染料（活性染料：AVITERA LIGHT RED SE）和非离子染料（分散染料：BEMACRON BLUE HP3R）的吸附性能。在接触时间（15-90 min）、吸附剂用量（20-60 g L -1）、pH（4和12）、温度（25-100℃）等条件下进行了批量吸附实验，并用紫外-可见光谱法测定了染料的浓度。当接触时间为30 min，室温为25℃时，在pH 4和pH 12条件下，阳离子染料的去除率分别为99.98%和99.93%，阴离子染料的去除率分别为65.26%和77.13%，非离子染料的去除率分别为94.04%和79.40%。对于非离子染料，在温度升高（接近60℃）时，去除率略有提高。动力学分析表明，阳离子染料的吸附符合伪二阶（PSO）模型（R2 = 0.9999），表明其化学吸附机制是由带负电荷的膨润土基面与静电相互作用驱动的。非离子染料吸附更符合伪一阶（PFO）模型（R2 = 0.9821），符合范德华力和氢键的物理吸附。阴离子染料对阳离子、阴离子和非离子染料的吸附均表现出较差的拟合（R2 1）。回收的染料在纺织品印花中重复使用，阳离子和非离子染料的印花稳定而鲜艳，阴离子染料的印花强度略有降低。这项工作证明了膨润土作为高效、低成本吸附剂和资源回收手段的双重作用，为跨多种染料类别的废水处理和染料再利用提供了新的见解。

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来源期刊

Environmental Science and Pollution Research 环境科学-环境科学

CiteScore

8.70

自引率

17.20%

发文量

6549

审稿时长

3.8 months

期刊介绍： Environmental Science and Pollution Research (ESPR) serves the international community in all areas of Environmental Science and related subjects with emphasis on chemical compounds. This includes: - Terrestrial Biology and Ecology - Aquatic Biology and Ecology - Atmospheric Chemistry - Environmental Microbiology/Biobased Energy Sources - Phytoremediation and Ecosystem Restoration - Environmental Analyses and Monitoring - Assessment of Risks and Interactions of Pollutants in the Environment - Conservation Biology and Sustainable Agriculture - Impact of Chemicals/Pollutants on Human and Animal Health It reports from a broad interdisciplinary outlook.