This study focuses on both ecological and economic gains from food waste treatment. Accordingly, anaerobic digestion and adsorption have been combined to achieve these goals, resulting in synergistic ...effects that improve productivity. Firstly, a considerable amount of methane (energy source) was produced by the anaerobic digestion of food waste (FW) under mesophilic conditions (38 °C), resulting in a biologically activated digestate. Secondly, the residue of anaerobic digestion (digestate) was utilized as raw material to design two types of low-cost adsorbents for dye removal: a carbon-based material (CM-HNO
3
) and an alginate encapsulated carbon-based material (CM-HNO
3
@Alginate beads). We evaluated the adsorption capacity of the designed carbon materials to eliminate the target pollutant methylene blue (MB) from aqueous solutions. The results show that the CM-HNO
3
and CM-HNO
3
@Alginate beads present maximum dye adsorption capacities of 303.03 mg g
−1
and 212.77 mg g
−1
, respectively. Further, the adsorption process was found to fit best to the Langmuir and pseudo-second-order kinetic models for both the adsorbents. In addition, the CM-HNO
3
@Alginate beads exhibited good long-term stability, regenerative ability, and high mass recovery, indicating that this absorbent is suitable for frequent usage.
This study focuses on both ecological and economic gains from food waste treatment.
This work presents a novel approach for the design and the stabilization of cobalt oxide nanoparticles supported on g-C
3
N
4
(CoCN-
x
) catalyst to efficiently degrade various organic pollutants ...through peroxymonosulfate (PMS) activation. The catalyst support synthesis process involved a two-step thermal treatment of urea, resulting in high-purity g-C
3
N
4
material, confirmed by XPS,
13
C NMR, and TGA analyses. Two cobalt oxide NP-based catalysts, CoO and α-Co(OH)
2
, were then prepared by depositing the cobalt nanoparticles on the g-C
3
N
4
support using gas-phase reduction by H
2
(CoCN-H
2
) and liquid-phase reduction by NaBH
4
(CoCN-NaBH
4
), respectively. The prepared CoCN-
x
materials were characterized using several techniques, such as FTIR spectroscopy, XRD, TEM, and SEM-EDS, which evidenced that the cobalt oxides were successfully introduced into g-C
3
N
4
. The effectiveness of the prepared catalysts in degrading organic contaminants was evaluated by activating PMS to generate reactive oxygen species (ROSs),
1
O
2
, SO
4
&z.rad;
−
, O
2
&z.rad;
−
, and HO&z.rad;, as confirmed through quenching experiments and electron paramagnetic resonance (EPR) analysis. These ROSs were responsible for the oxidation of the target contaminants, thereby promoting their mineralization. The results showed that both catalysts, CoCN-NaBH
4
and CoCN-H
2
, exhibited high catalytic activity throughout a wide pH spectrum, achieving hence complete degradation yields for various organic dyes, including OG, MO, BM, and RhB.
This work presents a novel approach for the design and the stabilization of cobalt oxide nanoparticles supported on g-C
3
N
4
(CoCN-
x
) catalyst to efficiently degrade various organic pollutants through peroxymonosulfate (PMS) activation.
This work presents a novel approach for the design and the stabilization of cobalt oxide nanoparticles supported on g-C 3 N 4 (CoCN- x ) catalyst to efficiently degrade various organic pollutants ...through peroxymonosulfate (PMS) activation. The catalyst support synthesis process involved a two-step thermal treatment of urea, resulting in high-purity g-C 3 N 4 material, confirmed by XPS, 13 C NMR, and TGA analyses. Two cobalt oxide NP-based catalysts, CoO and α-Co(OH) 2 , were then prepared by depositing the cobalt nanoparticles on the g-C 3 N 4 support using gas-phase reduction by H 2 (CoCN–H 2 ) and liquid-phase reduction by NaBH 4 (CoCN–NaBH 4 ), respectively. The prepared CoCN- x materials were characterized using several techniques, such as FTIR spectroscopy, XRD, TEM, and SEM-EDS, which evidenced that the cobalt oxides were successfully introduced into g-C 3 N 4 . The effectiveness of the prepared catalysts in degrading organic contaminants was evaluated by activating PMS to generate reactive oxygen species (ROSs), 1 O 2 , SO 4 ˙ − , O 2 ˙ − , and HO˙, as confirmed through quenching experiments and electron paramagnetic resonance (EPR) analysis. These ROSs were responsible for the oxidation of the target contaminants, thereby promoting their mineralization. The results showed that both catalysts, CoCN–NaBH 4 and CoCN–H 2 , exhibited high catalytic activity throughout a wide pH spectrum, achieving hence complete degradation yields for various organic dyes, including OG, MO, BM, and RhB.
A facile chemical procedure was utilized to produce an effective peroxy-monosulfate (PMS) activator, namely ZnCo
2
O
4
/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
2
O
4
and ZnCo
2
O
4
/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 ZnCo
2
O
4
/alginate catalyst displayed remarkable stability and reusability, as demonstrated by recycling tests. Additionally, quenching tests confirmed that SO
4
&z.rad;
−
/OH&z.rad; 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
2
O
4
/alginate.
In this work, a composite material, QS@PTh, comprising quartz-sand (QS) and polythiophene (PTh) was used for the activation of peroxymonosulfate (PMS) to degrade Orange G dye (OG). The QS@PTh ...composite was synthesized through a polymerization process that resulted in the attachment of polythiophene onto the quartz-sand surface. The formation of QS@PTh was demonstrated using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), and Fourier-transform infrared (FTIR) spectroscopy. The activation of PMS by the QS@PTh composite was evaluated through degradation experiments using Orange G dye as a model pollutant. The results demonstrated the efficient degradation of Orange G dye by the QS@PTh/PMS system, achieving a degradation efficiency of 99.5% and a COD removal of 79.4% within 60 min. The mechanism of PMS activation for OG degradation was suggested, highlighting the role of electron transfer from the polythiophene component to PMS, leading to the production of highly reactive species such as hydroxyl radicals (&z.rad;OH), sulfate radicals (SO
4
&z.rad;
−
), and singlet oxygen (
1
O
2
). Furthermore, the system exhibited remarkable efficacy in degrading other organic pollutants and real water samples, confirming its feasibility for decontaminating various pollutants. These promising results position QS@PTh/PMS as a versatile solution with potential application in the industrial sector. Additionally, the QS@PTh composite's catalytic activity remained robust even after five cycles, indicating its potential for repeated use. These outcomes collectively underscore the utility of QS@PTh as a performant catalyst for PMS activation in the degradation of organic contaminants, showcasing its potential for environmental remediation applications.
Synergistic effect of quartz-sand (QS) and polythiophene (PTh) in activating peroxymonosulfate (PMS) for the degradation of Orange G (OG) dye.
