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In this study, a straightforward and efficient method was employed to synthesize magnetic hybrid clays for wastewater treatment. The adsorbents were characterized through X-ray fluorescence, point of zero charge, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy coupled with energy-dispersive, and Brunauer–Emmett–Teller analyses. The results showed the presence of muscovite as a major phase, kaolinite and quartz, as well as Fe3O4, which was well attached to the hybrid clay, exhibiting a uniform structure. Surface area and pore volume significantly increased from 4.88 m2/g and 0.25 cm3/g for raw clay to 43 m2/g and 0.28 cm3/g for CT@Fe3O4. The properties of the adsorbents were evaluated for AB113 dye in batch adsorption experiments. The synthetic CT@Fe3O4 exhibited superior adsorption capacities, exceeding 90%. Fixed-bed column adsorption of AB113 using CT@Fe3O4 relied on factors such as the initial concentration of AB113, the flow rate, and the pH. The percentage removal of AB113 dye was found to be lower when the initial concentration increased from 20 to 50 mg/L, which also increased with the increasing flow rate. The removal rate reached a maximum value at pH 4, which is the optimal pH. Modeling and error analysis of the AB113 dye adsorption kinetics suggest that the Thomas and Yoon-Nelson models offer a more precise explanation of the experimental outcomes. The adsorption mechanism appeared to involve hydrogen bonding, π-π interactions, electrostatic forces, and Lewis base interactions. Hybrid clay thermally activated proves to be a suitable adsorbent for the sequestration of AB113 dye from aqueous solutions. [ABSTRACT FROM AUTHOR]

In this study, the modelling and optimization studies of the carcinogenic acid dye sorption from aqueous solutions were carried out using the Factor Design Methodology. This methodology provides a predictive model of the response in the range of variables studied and determines the optimum conditions for the best performance. The sorption of acid dye AB113 on Moroccan prickly pear cactus peel (MPPCP) was chosen as a case study of a typical removal process. Minitab17 software was used to study the effects of adsorption parameters, including initial dye concentration, solution pH, adsorbent dose, contact time, and temperature. Analysis of variance (ANOVA) was used to evaluate the experimental results obtained. The studied parameters at two levels (-1 and +1) were coded as X1, X2, X3, X4 and X5, consecutively. The optimum conditions obtained for the adsorption of AB113 dye were: 1 g for the mass of MPPCP, 6 for the initial solution pH, 180 min for the contact time and 20 mg/L for the initial dye concentration. The results show that the model is well adapted to the experimental data, indicating the suitability of the model and the success of the factorial design methodology in optimizing the adsorption conditions.

Water pollution is an alarming problem in developing countries. Dried algae can be considered as potential and suitable bio-sorbents due to their fast and easy growth and high availability. The special surface properties of these algae allow them to adsorb different types of organic and inorganic pollutants from solutions. In this context, the removal of anionic acid blue 113 dye (AB113) from aqueous solutions by dried Corallina officinalis alga as low-cost bio-sorbent was chosen as a case study of a typical remediation process of water contaminants. The effect of various environmental and physicochemical parameters has been studied. The results show that the equilibrium adsorption was established within 120 min. The sorption phenomenon was investigated by determining the process kinetics at different concentrations and the adsorption isotherms at different temperatures. The kinetics results showed that the pseudo second-order kinetics model generates the best agreement with the experimental data. The modeling results showed that linear Langmuir and Freundlich models appear to fit the adsorption data better than Temkin model for the adsorption of AB113 onto dried C. officinalis alga. It can be concluded that C. Officinalis alga can be successfully used as adsorbent.

In this study, effective biomaterials were prepared from marine macroalgae, namely Fucus spiralis (F.S), Ulva intestinalis (U.I), and Corallina officinalis (C.O). The ability to adsorb the hazardous organic dye crystal violet (CV) was examined, revealing different adsorptive properties for the three algae. The removal of CV dye occurred onto only a homogeneous monolayer for F.S, and both a homogeneous monolayer and a heterogeneous multilayer for U.I and C.O algae. The predicted monolayer capacities at 25 °C were approximately 53 mg/g, 55 mg/g, and 97 mg/g for F.S, C.O, and U.I, respectively. The adsorption of CV dye on all the algae was found to follow a pseudo-second-order rate. Ulva intestinalis algae, as a potential adsorbent of CV dye, were also tested in the adsorption of inorganic substances and demonstrated significant efficiency in the removal of chromium (VI). The findings highlight various adsorption properties and the relevance of macroalgae for wastewater treatment applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)