In the quest for sustainable waste management solutions, this study explores the integration of ultrasonic pretreatment as a preparatory step for the anaerobic digestion of landfill leachate. ...Employing response surface methodology (RSM) coupled with central composite design (CCD), we systematically optimize the process parameters, including pH, inoculum volume, and ultrasonic pretreatment duration, to maximize the yield of bio-methane potential (ml CH4/g VS). The results demonstrate the effective application of RSM-CCD for predicting and modelling methane generation, with a highly significant model (R2 = 0.899). The optimized conditions reveal a remarkable biomethane potential of 177 ml CH4/g VS. Additionally, this study contributes to the understanding of the positive effect of ultrasound pretreatment on the anaerobic digestion of landfill leachate, and the quality of the digestate obtained after anaerobic digestion was studied and different valorisations were proposed.
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•New synthesis approaches of Sulfur doped (S-PC), Nitrogen doped (N-PC) and Co-doped porous carbon (N, S-PC).•Novel commercially applicable environmental carbocatalysts for the ...catalytic oxidation of aqueous organic pollutants.•Activation of persulfate (PS) for organic pollutants degradation is proposed.•Electron transfer is achieved by N-doping (N-PC) compared to S (S-PC) and N/S Co-doping (N, S-PC).•Mechanism of degradation is proposed and computational study is investigated.
New green synthesis methods of novel commercially applicable carbocatalysts suitable for the catalytic oxidation of organic pollutants, remain a challenge. Herein, Nitrogen doped (N-PC), Sulfur doped (S-PC) and Co-doped (N, S-PC) porous carbon, were synthesized via a new facile environmentally functionalization approach followed by pyrolysis. Thus, Almond Shell (AS) as Bio-sourced material was used for porous carbon (PC) preparation as support. Thereafter, the introduction of Melamine, Diphenyl Disulfide and Thiourea on the PC matrix with high -COCl− and -CCl− groups facilitated the surface functionalization, and allowed us the introduction of high N and S heteroatoms contents in the PC networks surface. It was found that the optimized carbocatalysts could effectively activate PS, and exhibited excellent catalytic performances for the organic pollutants degradation, with an exceptionally low activation energy and fast kinetic reaction. Based on a systematic comparison, it was found that the N-PC exhibited the superior catalytic activity for activating the PS and degrading various organic pollutants. Such superior catalytic activity of the N-PC Carbocatalyst resulted from its high surface area, its low defect degree with the higher content of Graphitic-N. In addition, all experimental and theoretical investigations demonstrated the critical role of graphitic–N for the PS activation. It is expected that the doping process by N will significantly break the chemical inertness of the PC network and will make the N-PC surface more positively charged accelerating hence its interaction with the negatively charged S2O82−. Furthermore, the 1O2 was found to be the predominant reactive oxygen species (ROS) as assessed by radical scavenging tests and EPR experiments. The carbocatalysts were not easily influenced by the water aqueous phase, which give us more obvious advantages over the PS activation.
Anaerobic digestion is a highly effective and innovative method for treating organic waste while simultaneously generating energy. However, the treatment of the resulting digestate remains a ...challenging endeavor. To address this issue, poultry by-products digestate is used in this study to prepare biochars at two different pyrolysis temperatures (500/600 °C). Despite their potential, the utilization of untreated biochar is restricted due to its inadequate adsorption capacity. Therefore, each biochar was chemically activated using either HNO3 or KOH to synthesize four activated biochars (BC5@KOH, BC6@HNO3, BC5@HNO3, and BC6@HNO3). The aim is to investigate how the nature of chemical activation and pyrolysis temperature influence the adsorption of methylene blue dye. Characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, scanning electron microscopy (SEM), Raman analysis, and pHpzc determination, were exploited to comprehensively elucidate the structure and composition of both unprocessed and chemically activated biochars. Among the activated biochars, the adsorbent BC5@HNO3 exhibits the highest methylene blue (MB) adsorption capacity, reaching 101.72 mg.g−1 at 298 K under (pH = 2, ads dose = 0.6 g.L−1, shaking time of 20 min, as optimal conditions for MB adsorption. Adsorption data for each adsorbent strongly aligns with both the Langmuir isotherm model and the pseudo-second-order kinetic model. Moreover, the thermodynamic study reveals that the adsorption process was endothermic and spontaneous. The adsorption mechanism of MB dye was explored using various analytical techniques, including FTIR, SEM, PZC, and pH impact assessment. The findings suggest correlations with electrostatic interactions, hydrogen bonding, pore filling, as well as n-π and π-π interactions. Apparently, activated biochars play a crucial role in efficiently removing methylene blue dye, showcasing their potential as environmentally friendly and effective adsorbents.
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•Systematic investigation of thermochemical activation for biochar production.•Comprehensive physicochemical characterization of the activated biochars.•In-depth analysis of kinetics and isotherm models for MB removal.
In this study, quartz sand (QS) incorporated into a crosslinked chitosan-glutaraldehyde matrix (QS@Ch-Glu) was prepared and employed as an efficient adsorbent for the elimination of Orange G (OG) dye ...from water. The sorption process is adequately described by the pseudo-second order kinetic model and the Langmuir isotherm model with maximum adsorption capacities of 172.65, 188.18, and 206.65mg/g at 25, 35, and 45°C, respectively. A statistical physics model was adopted to elucidate the adsorption mechanism of OG on QS@Ch-Glu. Calculated thermodynamic factors revealed that the adsorption of OG is endothermic, spontaneous, and occurs via physical interactions. Overall, the proposed adsorption mechanism was based on electrostatic attractions, n-π stacking interaction, hydrogen bonding interaction, and Yoshida hydrogen bonding. The adsorption rate of QS@Ch-Glu was still above 95% even after 6 cycles of adsorption and desorption. Furthermore, QS@Ch-Glu demonstrated high efficiency in real water samples. All these findings demonstrate that QS@Ch-Glu is qualified for practical applications.
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•QS@Ch-Glu composite was synthesized by incorporation of quartz sand into glutaraldehyde crosslinked chitosan matrix.•Integration of quartz sand into glutaraldehyde crosslinked chitosan was confirmed by FTIR studies.•The regeneration process could be repeated at least six times.•Selectivity, and real water experiments were investigated to evaluate the suitability of QS@Ch-Glu in partical applications.•Statistical physics modeling was used to elucidate the adsorption mechanism of orange G on QS@Ch-Glu.
The presented discovery provides a long-term strategy for successfully utilizing quartz sand (QS) as a low-cost, efficient, and environmentally friendly adsorbent. To improve the adsorption capacity ...and efficiency, a new chemical strategy was used to coat the QS particles with polyaniline (PANI), creating a hybrid material composite (QS@PANI). The prepared composite's ability to effectively remove Orange G dye (OG) from aqueous solutions was investigated through a series of batch adsorption experiments. The highest removal efficiency was due to the synergistic effect of the QS and the PANI, which favors electrostatic interaction, π-π interaction, and hydrogen bonding due to the nitrogen atoms in their conjugated chains. Adsorption kinetics were described by the pseudo-second-order, and Elovich models, while equilibrium capacity was described by the Langmuir adsorption model. Interestingly, after six repeated cycles, the composites unveiled a high removal proficiency >82% at different pH (2–8) of the solution and possessed an excellent adsorptive property, providing a cost-effective material for decolorization applications. Density functional theory (DFT) calculations and molecular dynamics simulations were utilized to elucidate the adsorption mechanism. The results showed that Orange G adsorption on QS@PANI occurs via a physisorption process. This research not only provided a structure-function relationship for PANI-QS organic-inorganic composite material assemblies, but it also provided an encouraging framework for the long-term advancement of water purification technology.
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•The synergistic effect between HS and the conducting polymers displayed excellent catalytic properties.•Conducting polymers is an electronic mediator to promote the conversion of Fe ...(III) to Fe (II).•Conjugated systems of PANI and PPy can facilitate the electron transfer during the PS activation.•Protective polymer layers prevented metal ion leaching and enabled pH insensitive persulfate activation.•HS@PANI and HS@PPy catalysts mitigate deactivation and allow facile regeneration.
This study explores new chemical strategies for coating the hematite sand (HS) by conductive polymers to enhance the persulfate activation performance. The highest catalytic activity was due to synergistic effect between the HS and the conductive polymers. In fact, conjugated polymers could act as an activator and electronic mediator to promote the conversion of Fe (III) to Fe (II). Hence, both conductive polymers used (polyaniline and polypyrrole) have been found to provide the necessary electron transfer, thanks to their nitrogen atoms located in their conjugated chains. The radical scavenging experiments assessed by electronic paramagnetic resonance indicated that the studied pathways nature was both a radical and non-radical type. Further, it was found that the protective polymer layers prevented metal ion leaching, mitigate catalyst deactivation, enabled pH insensitive persulfate activation, and increased the chemical stability. This work provides a new innovative way to remove multiple pollutants in wastewater.
In this paper, we present a new catalyst based on graphene oxide deposited on PES fabric and decorated with Cu0 and Ag0 NPs. The material was created via dip-coating followed by in-situ reduction of ...Cu2+ and Ag+ to Cu0 and Ag0 on its surface. Different physico-chemical characterizations were performed to investigate the possible interfacial interactions between PES, GO, and metallic ions. The PES-GO/Cu0-Ag0 was evaluated for the reduction of 4-nitrophenol (0.03. 10-3 M), Rhodamine B (20 ppm) and Methyl Orange (20 ppm). The PES-GO/Cu0-Ag0 catalyst shows outstanding catalytic activity for the reduction of all organic compounds tested. The reaction constant for 4-NP, RhB, and MO was 0.564, 0.569, and 0.42 min-1, respectively. Furthermore, the findings indicate that PES-GO/Cu0-Ag0 coatings on PES substrate may be advantageous to avoid problems with powder separation.
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A facile chemical procedure was utilized to produce an effective peroxy-monosulfate (PMS) activator, namely ZnCo2O4/alginate. To enhance the degradation efficiency of Rhodamine B (RhB), a novel ...response surface methodology (RSM) based on the Box–Behnken Design (BBD) method was employed. Physical and chemical properties of each catalyst (ZnCo2O4 and ZnCo2O4/alginate) were characterized using several techniques, such as FTIR, TGA, XRD, SEM, and TEM. By employing BBD-RSM with a quadratic statistical model and ANOVA analysis, the optimal conditions for RhB decomposition were mathematically determined, based on four parameters including catalyst dose, PMS dose, RhB concentration, and reaction time. The optimal conditions were achieved at a PMS dose of 1 g l−1, a catalyst dose of 1 g l−1, a dye concentration of 25 mg l−1, and a time of 40 min, with a RhB decomposition efficacy of 98%. The ZnCo2O4/alginate catalyst displayed remarkable stability and reusability, as demonstrated by recycling tests. Additionally, quenching tests confirmed that SO4·−/OH· radicals played a crucial role in the RhB decomposition process.
A facile chemical procedure was utilized to produce an effective peroxy-monosulfate (PMS) activator, namely ZnCo
O
/alginate. To enhance the degradation efficiency of Rhodamine B (RhB), a novel ...response surface methodology (RSM) based on the Box-Behnken Design (BBD) method was employed. Physical and chemical properties of each catalyst (ZnCo
O
and ZnCo
O
/alginate) were characterized using several techniques, such as FTIR, TGA, XRD, SEM, and TEM. By employing BBD-RSM with a quadratic statistical model and ANOVA analysis, the optimal conditions for RhB decomposition were mathematically determined, based on four parameters including catalyst dose, PMS dose, RhB concentration, and reaction time. The optimal conditions were achieved at a PMS dose of 1 g l
, a catalyst dose of 1 g l
, a dye concentration of 25 mg l
, and a time of 40 min, with a RhB decomposition efficacy of 98%. The ZnCo
O
/alginate catalyst displayed remarkable stability and reusability, as demonstrated by recycling tests. Additionally, quenching tests confirmed that SO
˙
/OH˙ radicals played a crucial role in the RhB decomposition process.
The release of liquid effluents containing heavy metals, notably Cr (VI), into the environment is a significant contributor to water pollution. Consequently, there is a growing concern about treating ...these effluents before their discharge. In this context, our study introduces an innovative approach to produce a novel chloride-doped polypyrrole/Diatomite (Cl-PPy/DT) nanocomposite through in situ polymerization. We examined the physicochemical properties of Cl-PPy/DT using various analytical techniques, including structural, textural, morphological, and thermal analyses, confirming the successful formation of the composite. For Cr (VI) removal via batch adsorption, the efficiency of Cl-PPy/DT surpassed that of Cl-PPy and diatomite by 2.21 and 3.75 times, respectively, at a Cr(VI) concentration of 25 ppm. This suggests a robust synergistic effect between diatomite and Cl-PPy, where both components resist aggregation, resulting in a loose structure and optimal exposure of active sites. Using response surface methodology, we refined adsorption parameters such as contact time, initial metal concentration, and adsorbent quantity. Results indicated that adsorption followed a quadratic polynomial model with high regression parameters (R2 value = 99.6%). Kinetic findings demonstrated that Cr(VI) adsorption on Cl-PPy/DT aligned with the pseudo-second-order model. Moreover, at 25 °C, the Langmuir model effectively correlated with equilibrium data, revealing a maximum adsorption capacity (qmax) of 89.97 mg/g for the Cl-PPy/DT adsorbent. Notably, the adsorbent exhibited renewability and reusability for up to four cycles, indicating its potential for large-scale use as a competitive adsorbent.
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•New stable diatomite-polypyrrole composite was successfully synthesized and applied for Cr(VI) removal.•PPY@Diatomite provides a High adsorption ability for Cr (VI) in aqueous solutions.•Response surface methodology was applied to optimize the Cr (VI) adsorption behavior.•PPY@Diatomite was a promising and reusable material for Cr(VI) removal.
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