The Enhanced Adsorption Capacity of <em>Ziziphus jujuba</em> Stones Modified with Ortho-Phosphoric Acid for Organic Dye Removal: A Gaussian Process Regression Approach

\ua9 2024 by the authors. Here, the chemical modification of Ziziphus jujuba stones (ZJS) treated with ortho-phosphoric acid (ZJS-H3PO4) is investigated to enhance its adsorption properties for organic dyes. The physicochemical properties of ZJS-H3PO4 reveal increased porosity (87.29%), slightly higher bulk density (0.034 g mL−1), and enhanced acidity (31.42 m eq g g−1) compared to untreated ZJS. XRF analysis confirms the successful incorporation of orthophosphoric acid during treatment due to a significant increase in phosphorus content. The maximum adsorption capacity of methylene blue on ZJS-H3PO4 is found to be 179.83 mg g−1, demonstrating its efficacy as a potential adsorbent for organic dyes. These findings suggest that modifying ZJS with orthophosphoric acid could be a promising strategy to enhance its adsorption performance in various environmental applications. Furthermore, Gaussian process regression (GPR) is employed to model MB adsorption by ZJS-H3PO4. Optimization of the GPR model involves evaluating different kernel functions and meticulously adjusting parameters to maximize its ability to capture complex relationships in the data. The obtained GPR model demonstrates remarkable performance with high correlation coefficients (R) and low root mean square errors (RMSEs) across all study phases. Model validation is performed through residual analysis, confirming its effectiveness and accuracy in predicting MB adsorption. Finally, a user-friendly interface is developed to facilitate the usage of the GPR model in future applications, representing a significant advancement in environmental process modeling and ecosystem management

Enhanced photocatalytic degradation of methylene blue: Preparation of TiO2/reduced graphene oxide nanocomposites by direct sol-gel and hydrothermal methods

In this study, two different preparation methods of titanium dioxide nanoparticles/reduced graphene oxide nanocomposites were investigated using direct sol-gel method followed by hydrothermal treatment or simple hydrothermal route. A different amount of graphene (1- 20%) was mixed with TiO2 for both series of samples in order to improve the photocatalytic activity. The influence of the preparation method on the physico-chemical properties was established by different characterization methods and the photocatalytic degradation of methylene blue (MB) under UV light irradiation was used as test reaction. The highest photocatalytic activity was observed for the nanocomposites containing 10 wt% of graphene. The elimination of MB can reach 93% and 82% for the nanocomposites with 10 wt% graphene prepared by the sol-gel and hydrothermal methods, respectively. These photocatalysts are promising for practical application in nanotechnology.Postprint (author's final draft

Evaluating the Effectiveness of Coagulation–Flocculation Treatment Using Aluminum Sulfate on a Polluted Surface Water Source: A Year-Long Study

\ua9 2024 by the authors.Safeguarding drinking water is a major public health and environmental concern because it is essential to human life but may contain pollutants that can cause illness or harm the environment. Therefore, continuous research is necessary to improve water treatment methods and guarantee its quality. As part of this study, the effectiveness of coagulation–flocculation treatment using aluminum sulfate (Al2(SO4)3) was evaluated on a very polluted site. Samplings were taken almost every day for a month from the polluted site, and the samples were characterized by several physicochemical properties, such as hydrogen potential (pH), electrical conductivity, turbidity, organic matter, ammonium (NH+4), phosphate (PO43−), nitrate (NO3−), nitrite (NO2−), calcium (Ca2+), magnesium (Mg2+), total hardness (TH), chloride (Cl−), bicarbonate (HCO3−), sulfate (SO42−), iron (Fe3+), manganese (Mn2+), aluminum (Al3+), potassium (K+), sodium (Na+), complete alkalimetric titration (TAC), and dry residue (DR). Then, these samples were treated with Al2(SO4)3 using the jar test method, which is a common method to determine the optimal amount of coagulant to add to the water based on its physicochemical characteristics. A mathematical model had been previously created using the support vector machine method to predict the dose of coagulant according to the parameters of temperature, pH, TAC, conductivity, and turbidity. This Al2(SO4)3 treatment step was repeated at the end of each month for a year, and a second characterization of the physicochemical parameters was carried out in order to compare them with those of the raw water. The results showed a very effective elimination of the various pollutions, with a very high rate, thus demonstrating the effectiveness of the Al2(SO4)3. The physicochemical parameters measured after the treatment showed a significant reduction in the majority of the physicochemical parameters. These results demonstrated that the coagulation–flocculation treatment with Al2(SO4)3 was very effective in eliminating the various pollutions present in the raw water. They also stress the importance of continued research in the field of water treatment to improve the quality of drinking water and protect public health and the environment

Microscopic Study of Superdeformed Rotational Bands in 151Tb

Structure of eight superdeformed bands in the nucleus 151Tb is analyzed using the results of the Hartree-Fock and Woods-Saxon cranking approaches. It is demonstrated that far going similarities between the two approaches exist and predictions related to the structure of rotational bands calculated within the two models are nearly parallel. An interpretation scenario for the structure of the superdeformed bands is presented and predictions related to the exit spins are made. Small but systematic discrepancies between experiment and theory, analyzed in terms of the dynamical moments, J(2), are shown to exist. The pairing correlations taken into account by using the particle-number-projection technique are shown to increase the disagreement. Sources of these systematic discrepancies are discussed -- they are most likely related to the yet not optimal parametrization of the nuclear interactions used.Comment: 32 RevTeX pages, 15 figures included, submitted to Physical Review

The use of encapsulation as a proposed solution to avoid problems encountered with conventional materials in powder form Application in methylene blue removal from aqueous solutions

International audienceThe Ziziphus jujuba stones chemically modified with orthophosphoric acid (PZJS), then encapsulated with sodium alginate (BZJS1 and BZJS2) were used for organic dye adsorption. In this context, the basic dye methylene blue (MB) was chosen as a test molecule. The characteristics of the prepared beads were examined by different characterization techniques, such as Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray diffraction (EDX), X-ray fluorescence (XRF), Thermogravimetric analysis (TGA) and Brunauer–Emmett–Teller method (BET) with nitrogen adsorption-desorption isotherm at 77 °K. In a batch system, initial pH (2−12), temperature (10, 25, 30 and 40 °C), initial concentration (50–200 mg/L), contact time, salt and organic compound effects were studied. The obtained results showed that the maximum MB adsorption amounts were 737.13 mg/g and 660.12 mg/g onto BZJS1 and BZJS2 at ambient temperature respectively, showing that the prepared materials are more efficient than most of the other adsorbents. Moreover, experimental data modeling showed that the adsorption process followed the Redlich-Peterson model. Regarding kinetics modeling, pseudo-first-order (PFO), pseudo-second-order and Pseudo-nth order models were used to correlate experimental data, demonstrating that a mass transfer equation (PFO) could describe MB adsorption. Thermodynamic parameters were also evaluated, demonstrating that the MB adsorption process was achievable, spontaneous and exothermic. The regeneration study showed that both of the beads had excellent adsorption efficiency even at the sixth cycle for the two beads, 92.01 and 82.88 for BZJS1 and BZJS2, respectively. From this and in view of a future implementation at industrial scale, encapsulation by sodium alginate polymer can be therefore promisingly proposed as a solution to avoid the problems of conventional materials in powder form, such as the difficulty of regeneration, performances and mass loss during the recovery step of the powder from the medium. © 202

Novel activated carbon prepared from an agricultural waste, Stipa tenacissima, based on ZnCl2 activation—characterization and application to the removal of methylene blue

International audienceActivated carbon (AC) was prepared by means of a novel physiochemical activation method from low-cost biosorbent, agricultural waste (Stipa tenacissima fiber). A two-step pyrolysis was considered instead of a single-step pyrolysis, which involved zinc chloride for the first activation step and a steam mixture of water, CO2 and acetic acid for the second step. The obtained AC was tested as an adsorbent for the removal of a basic dye, Methylene blue (MB) from aqueous solutions. Batch experiments were conducted to examine the effect of the main parameters, such as the initial MB concentration, the pH, and the kinetic adsorption of this dye. Results showed that a pH value of 7 is favorable for the adsorption of MB. Rate constants of pseudo-first-order, pseudo-second-order, and intraparticle diffusion coefficient were calculated to analyze the dynamic of the adsorption process; they showed that adsorption kinetics followed a pseudo-second-order and an intraparticle diffusion model, while the two straight lines describing experimental data indicated that intraparticle diffusion was not the limiting mechanism for adsorption. Among the tested isotherm models, the Sips isotherm was found to be the most relevant to describe MB adsorption onto both activated and non-ACs with the best maximum adsorption capacity (Qm), 178.44 and 27.21 mg g−1, respectively. The negative values of ΔG° revealed that the adsorption process was spontaneous. The positive values of ΔH° and ΔS° showed the endothermic nature and an increase in disorder of MB molecules during the adsorption process, respectively. © 2016 Balaban Desalination Publications. All rights reserved

Thermodynamic study and the development of a support vector machine model for predicting adsorption behavior of orange peel-derived beads in wastewater treatment

\ua9 2024 Elsevier B.V.This study investigates the use of orange peels as a precursor for synthesizing sodium alginate-encapsulated beads for methylene blue (MB) removal. The prepared beads (BOP1 and BOP2) underwent characterization through FTIR, XRF, SEM and TGA. Subsequently, the impacts of various factors, including temperature, the initial pH, initial concentration, salt and humic acid, are studied. The adsorption isotherms show high adsorbed quantities of 764.92 and 659.78 mg/g for BOP1 and BOP2 respectively, while the obtained data are best described by the monolayer with two energies (MMTE) model, which is then used to perform a thermodynamic study of the MB adsorption mechanism. Additionally, the adsorption kinetics data are modeled using three models, with the PFO model identified as the most appropriate. The regenerated beads demonstrate the ability to be reused up to 7 cycles, The effects of NaCl and humic acid on MB adsorption reveal that NaCl inhibits adsorption due to competition with Na+, while humic acid has no effect. Finally, a support vector machine (SVM) model optimized by the Levy Flight Distribution Optimization (LFD) algorithm is developed and found to be capable of accurately predicting the adsorption behavior of the prepared beads. This model is then used in optimizing the process conditions for maximal MB removal. Overall, this study demonstrates that the prepared beads could be potential low-cost and environmentally friendly adsorbents for wastewater treatment applications

Removal of the anionic dye Biebrich scarlet from water by adsorption to calcined and non-calcined Mg–Al layered double hydroxides

International audienceA native layered double hydroxide Mg–Al–CO3, denominated LDH, containing Mg(II) and Al(III) in the layers, was prepared by a co-precipitation method. Its calcined form Mg–Al, (CLDH), was obtained by calcination at 500°C. Both materials were characterized by powder X-ray diffraction (PXRD), Fourier transformation infrared spectroscopy, thermogravimetric analysis, and the determination of the point of zero charge. The porous structure of the solids was investigated by nitrogen adsorption at 77 K. The adsorptive affinity of these materials for Biebrich Scarlet was studied as a function of dye–adsorbent contact time, initial pH of the solution, initial dye concentration, and temperature. Sorption kinetics data fitted best to a pseudo-second-order model suggesting that the process of BS adsorption is controlled by reaction rate for interaction of dye molecules rather than by diffusion. Equilibrium data for both adsorbents were in accordance with both Sips and Langmuir isotherm models. The sorption capacity of CLDH was found to be almost independent on the initial pH, while sorption capacity of LDH was lower in neutral and alkaline conditions than at acidic pH. The adsorption process was also found to be spontaneous and endothermic in nature. © 2016 Balaban Desalination Publications. All rights reserved