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

Osmotic dehydration of some agro-food tissue pre-treated by pulsed electric field: Impact of impeller’s Reynolds number on mass transfer and color

Tissues of apple, carrot and banana were pre-treated by pulsed electric field (PEF) and subsequently osmotically dehydrated in an agitated flask at ambient temperature using a 65% sucrose solution as osmotic medium. The effect of stirring intensity was investigated through water loss (WL) and solid gain (SG). Changes in product color were also considered to analyze the impact of the treatment. The impeller’s Reynolds number was used to quantify the agitation. The Reynolds number remained inferior to 300 thus displaying laminar flow regime. Water loss (WL) and solid gain (SG) increase with the increase of Reynolds number. Mass transfer in osmotic dehydration of all three test particles has been studied on the basis of a two-exponential kinetic model. Then, mass transfer coefficients were related to the agitation intensity. This paper shows that the proposed empirical model is able to describe mass transfer phenomena in osmotic dehydration of these tissues. It is also shown that a higher agitation intensity improves both the kinetics of water loss and solid gain

Activated carbon from thermo-compressed wood and other lignocellulosic precursors

The effects of thermo-compression on the physical properties such as bulk density, mass yield, surface area, and also adsorption capacity of activated carbon were studied. The activated carbon samples were prepared from thermo-compressed and virgin fir-wood by two methods, a physical activation with CO2 and a chemical activation with KOH. A preliminary thermo-compression method seems an easy way to confer to a tender wood a bulk density almost three times larger than its initial density. Thermo-compression increased yield regardless of the mode of activation. The physical activation caused structural alteration, which enhanced the enlargement of micropores and even their degradation, leading to the formation of mesopores. Chemical activation conferred to activated carbon a heterogeneous and exclusively microporous nature. Moreover, when coupled to chemical activation, thermo-compression resulted in a satisfactory yield (23%), a high surface area (>1700 m2.g-1), and a good adsorption capacity for two model pollutants in aqueous solution: methylene blue and phenol. Activated carbon prepared from thermo-compressed wood exhibited a higher adsorption capacity for both the pollutants than did a commercial activated carbon

High efficient Cefixime removal from water by the sillenite Bi12TiO20: Photocatalytic mechanism and degradation pathway

International audienceWater pollution is a significant concern that affects the environment and human health. Antibiotics are among the most dangerous types of pollutants spreading in our time because of their harmful effects, such as generating antibiotic-resistant bacteria. Therefore, it is necessary to attain an eco-friendly and efficient method for treating those hazardous compounds. This study proposes a clean approach for removing antibiotics from pharmaceutical wastewater, using an efficient photocatalyst Bi12TiO20 (BTO) synthesized by the sol-gel method. Several characterizations were carried out to identify the obtained catalyst, such as XRD, BET, Raman, FESEM, EDX with elemental mapping, TEM, UV–Vis, and PL, in which the space group of BTO crystals was discovered to be I23, with a bandgap of 2.9 eV. To evaluate the photocatalytic properties of the catalyst BTO, Cefixime (CFX) was chosen as a pollutant example. The photocatalytic efficiency was optimized using an artificial neural network (ANN) method with a deep learning technique. The ANN network was trained using experimental data with various BTO dosages and CFX initial concentrations at varying pH. The results have shown that the BTO catalyst can lead to 94.93% CFX degradation and 87.66% mineralization within only 3 h, this efficiency was very high compared to other catalysts used in previous studies. The relative importance of different photocatalytic parameters was estimated using ANN data, the highest effective parameter was the initial CFX concentration. Then, the by-products were analyzed using GC-MS, and a pathway for CFX degradation was suggested. The mechanism of the degradation was also investigated in the presence of scavenger agents. The results showed that the CFX molecules had been degraded totally into tiny molecules, proving the efficient performance of this catalyst. These findings make this sillenite an effective catalyst for removing antibiotics from the aquatic environment. © 2021 Elsevier Lt

Study of Barium Adsorption from Aqueous Solutions Using Copper Ferrite and Copper Ferrite/rGO Magnetic Adsorbents

The development of advanced materials for the removal of heavy metal ions is a never-ending quest of environmental remediation. In this study, a facile and cost-effective approach was employed to synthesize copper ferrite (CF) and copper ferrite/reduced graphene oxide (CG) by microwave assisted combustion method for potential removal of barium ions from aqueous medium. The physiochemical characterizations indicated the formation of magnetic nanocomposite with an average crystallite size of CF and CG is 32.4 and 30.3 nm and with specific surface area of 0.66 and 5.74 m2/g. The magnetic results possess multidomain microstructures with saturation magnetization of 37.11 and 33.84 emu/g for CF and CG. The adsorption studies prove that upon addition of rGO on the spherical spinel ferrite, the adsorption performance was greatly improved for CG nanocomposite when compared with the bare CF nanoparticles. The proposed magnetic adsorbent demonstrated a relatively high Ba2+ adsorption capacity of 161.6 mg·g-1 for CG nanocomposite when compared to 86.6 mg·g-1 for CF nanoparticles under optimum conditions (pH=7;T=25°C). The pseudo-first-order (PFO), pseudo-second-order (PSO), and Elovich models were fitted to the kinetic data, the yielded R2 value of 0.9993 (PSO) for CF and 0.9994 (PSO) for CG which is greater than the other two models, which signify that the adsorption process is chemisorption. Thermodynamic studies show that barium adsorption using CF and CG adsorbents is endothermic. The as-fabricated CuFe2O4/rGO nanocomposite represents a propitious candidate for the removal of heavy metal ions from aqueous solutions

Harmonizing the photocatalytic activity of g-C3N4 nanosheets by ZrO2 stuffing: From fabrication to experimental study for the wastewater treatment

International audienceZrO2 @g-C3N4 photocomposite has been prepared from ZrO2 nanoparticles and g-C3N4 nanosheet using methanol via the ultrasonic method. The prepared photocomposite was characterized using XRD, TEM, EDX, DRS, FTIR, and XPS techniques and compared with pure ZrO2 and g-C3N4. A comparative study between the photocatalytic performance of the nanocomposite prepared material with ZrO2 and g-C3N4 used to degrade indigo carmine (IC) dye in an aqueous suspension has been developed. The experimental photodegradation data were asserted to conform to the Lagergren kinetics model, and the fabricated nanocomposite registers a higher rate constant and lower half-life time than pure g-C3N4. The findings showed that ZrO2 nanomaterials were adequately predisposed on the g-C3N4 surface, resulting in an expanded surface area and lowering band-gap energy. Furthermore, ZrO2 @g-C3N4 heterojunctions fabricated was hindered the recombination of superoxide radicals, electrons, and holes and resulted in the magnified photodegradation of IC dye

Superior removal of dyes by mesoporous MgO/g-C(3)N(4) fabricated through ultrasound method: Adsorption mechanism and process modeling

International audienceThe present research concerns the synthesis of a mesoporous composite characterized with high surface area and superior adsorption capacity in order to investigate its efficacity in removing hazardous and harmful dyes molecules from water. The synthesized mesoporous composite, MgO/g-C(3)N(4) (MGCN), was successfully prepared through the sonication method in a methanolic solution followed by an evaporation and a calcination process. The configuration, crystalline phase, surface properties, chemical bonding, and morphological study of the fabricated nanomaterials were investigated via XRD, BET, FESEM, HRTEM, XPS, and FTIR instrumentation. The obtained nanomaterials were used as sorbents of Congo Red (CR) and Basic Fuchsin (BF) dyes from aqueous solutions. Batch elimination experimental studies reveal that the elimination of CR and BF dyes from an aqueous solution onto the MGCN surface was pH-dependent. The highest removal of CR and BF pollutants occurs, respectively, at pH 5 and 7. The absorptive elimination of CR and BF dyes into the MGCN surface was well-fitted with a pseudo-second-order kinetics and Langmuir model. In this concern, the maximum nanocomposite elimination capacity for CR and BF was observed to be 1250 and 1791 mg g(-1), respectively. This investigation confirms that MGCN composite is an obvious and efficient adsorbent of CR, BF, and other organic dyes from wastewater