Removal of Reactive Blue 19 from simulated textile wastewater by Powdered Activated Carbon/Maghemite composite

Improved Setup for Decolourization Experiments with Granular and Powdered Adsorbent Materials Using UV-VIS Flow-through Cells

Textile wastewater treatment poses global challenges due to complex and costly processes, particularly in the adsorption-based decolourization step. Existing experimental methodologies for adsorption suffer from inconsistencies, hindering comparability across studies. To address this, we developed a universal setup integrating conventional adsorption methods with pharmaceutical dissolution techniques. This approach provides continuous UV-VIS monitoring of adsorption processes without external filtration, which is suitable for both fine powders (∼microns) and granular particles (∼millimetres) and is applicable to both natural and synthetic adsorbents. Case studies conducted with powdered and granular adsorbents confirmed this method's robustness, reproducibility, and enhanced accuracy, allowing real-time, precise monitoring. Overall, this versatile approach significantly improves reliability in adsorption experiments, offering a broadly applicable solution for adsorption monitoring in wastewater treatment research.•A versatile setup combining adsorption methods with flow-through UV-VIS spectrometry.•Enables continuous monitoring of decolourization without the need for external filtration.•Applicable to a wide range of adsorbent materials, from fine powders to granulates.

Decolourization properties of pure phases in hydrated cement paste for anionic dyes in textile wastewater

The rise of fast fashion has increased the need for cost-effective adsorbents in textile wastewater treatment. Cementitious materials have shown promising decolourizing properties in anionic dye solutions. This study evaluates the decolourization properties of a selection of phases typically present in hydrated cement paste, such as calcium-(alumino)-silicate-hydrate (C-(A)-S-H) phases, hydrotalcite, and monocarboaluminate. Three anionic dyes were tested in combination with different salts, which are used in textile dyeing. Reactive Blue 19 was adsorbed more effectively than the other dyes. C-(A)-S-H phases performed best in basic environments, while layered structures excelled in acidic conditions, with monocarboaluminate reaching over 250 mg/g at pH 5. The presence of salts significantly affected adsorption, with MgSO4 mainly enhancing the decolourization up to 178 mg/g for monocarboaluminate and NaCl reducing capacities to a maximum adsorption of 95 mg/g for hydrotalcite. For hydrotalcite and monocarboaluminate, the effect of pH and presence of salts on the overall decolourization could be explained by a linear correlation between the zeta potential of the solid phases and their decolourization capacity. These findings provide valuable insights into the potential of cementitious materials as low-cost adsorbents in the treatment of coloured textile wastewater.

Biomagnetic chitosan-ethylene glycol diglycidyl ether/organo-nanoclay nanocomposite for azo dye removal: A statistical modeling by response surface methodology

Herein, a quadruple biomagnetic nanocomposite of cross-linked chitosan-ethylene glycol diglycidyl ether/organo-nanoclay (MCH-EGDE/ORNC) was designed for the uptake of remazol brilliant blue R (RBBR) dye from aqueous environment. The adsorption process was systematically improved via the Box-Behnken design (BBD) to determine the influence of key uptake parameters, including MCH-EGDE/ORNC dosage, pH, and time, on the RBBR removal. The highest RBBR removal of 87.5 % was achieved at the following conditions: MCH-EGDE/ORNC dosage: 0.1 g/100 mL; pH: 4.0; contact time: 25 min. The findings of the kinetics and equilibrium studies revealed an excellent fit to the pseudo-second order and the Freundlich models, respectively. The adsorption capacity of the MCH-EGDE/ORNC for RBBR was found to be 168.4 mg/g, showcasing its remarkable adsorption capability. The present work highlights the potential of MCH-EGDE/ORNC biomaterial as an advanced adsorbent and lays the foundation for future applications in water purification and environmental remediation.

Study on the Adsorption Properties of Oxalic Acid-Modified Cordierite Honeycomb Ceramics for Neutral Red Dyes

Removal of organic dyes from water by monolithic adsorbents is considered as an efficient and no-secondary pollution method. Herein, for the first time cordierite honeycomb ceramics (COR) treated with oxalic acid (CORA) were synthesized. This CORA exhibits outstanding removal efficiency toward the azo neutral red dyes (NR) from water. After optimizing the reaction conditions, the highest adsorption capacity of 7.35 mg·g^-1 and a removal rate of 98.89% could be achieved within 300 min. Furthermore, investigation of the adsorption kinetics indicated this adsorption process could be described as a pseudo-second-order kinetic model with k ₂ and q _e of 0.0114 g·mg^-1·min^-1 and 6.94 mg·g^-1, respectively. According to the fitting calculation, the adsorption isotherm could also be described as the Freundlich isotherm model. The removal efficiency could be maintained above 50% after 4 cycles, negating the need for toxic organic solvent extraction, offering a method for bringing the technology one step closer to industrial application and giving CORA promising potential in practical water treatment.