Influence of mixed methods on the surface area and gas products of activated carbon

Hwang, Sohyun; Bbum, Lee Gi; Ho, Kim Dong; Eun, Park Jung

doi:10.1007/s42823-020-00130-4

Cited by 7 publications

(4 citation statements)

References 38 publications

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“…Such a reduced specific surface area may compromise the composite’s adsorption efficiency. 41 − 43 This deduction, depicted in Figure 4 b,c, aligns with the SEM results. Figure 4 a highlights that the silver phosphate concentration had a negligible impact on the AC average pore size, which remained stable at ∼2.3 nm.…”

Section: Resultssupporting

confidence: 87%

Straw-Derived Activated Carbon Decorated with Ag₃PO₄ for Organic Pollutant Removal by a Circular Degradation Mechanism: Adsorption and Photocatalysis

Yue,

Han,

Ding

et al. 2024

ACS Omega

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The escalating problem of water pollution has become an urgent concern, as it significantly undermines people’s quality of life and overall public health. The increasing severity of water pollution represents a global challenge, with profound implications for human society. In this study, hydrothermal carbonization coupled with alkaline activation was utilized to repurpose barley straw into activated carbon (AC) as an absorbent. Silver phosphate (Ag3PO4) was synthesized as a potent photocatalyst. Subsequent ultrasound-assisted loading integrated the robust adsorptive capabilities of the AC with the advanced photocatalytic efficiency of silver phosphate, resulting in a superior composite material (AC/Ag3PO4) and implementing a novel “absorption–photocatalysis” active circular degradation strategy to remove hazardous organics in water. Comprehensive characterization assays confirmed the successful synthesis and incorporation of Ag3PO4 onto the AC scaffold. The composite with a Ag3PO4 concentration of 3 wt % exhibited a high methylene blue (MB) removal efficiency of 99.4% within 100 min. The reaction rate of this composite surpassed that of standalone AC by a factor of 2.89. Furthermore, cyclic regeneration studies via adsorption–desorption methodologies revealed the composite’s resilience and sustained performance. The MB removal efficiency was maintained at 85.5% over five consecutive cycles, demonstrating the composite’s remarkable stability. The integration of adsorptive and photocatalytic functionalities within a single system mitigates potential secondary pollution arising during the AC’s desorption phase and enhances the organic contaminant removal efficiency. Moreover, the utilization of this integrated material reduces the quantity of chemicals and energy required for conventional adsorption water treatment techniques, as the material harnesses sunlight or alternative light sources to catalyze contaminant decomposition. This reduces the dependence on chemical treatment agents, contributing to resource conservation and alleviating environmental burdens. This pioneering approach offers a novel paradigm for addressing pollutant challenges in aqueous environments.

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Section: Resultssupporting

confidence: 87%

Straw-Derived Activated Carbon Decorated with Ag₃PO₄ for Organic Pollutant Removal by a Circular Degradation Mechanism: Adsorption and Photocatalysis

Yue,

Han,

Ding

et al. 2024

ACS Omega

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“…The main reaction of HTC is dehydration, but decarboxylation and decarboxylation may occur, depending on the reaction conditions. In general, CO2 from the carboxyl group is emitted at a lower temperature than CO from carbonyl groups, and the carbonyl group is desorbed at high temperatures [23,30,31]. The decrease in the H/O atomic ratio is affected by carbonylation, consistent with the results of gas emissions from a secondary reaction in which carbonation is performed in the liquid phase.…”

Section: Htc Of Scgs At Different Reaction Timessupporting

confidence: 72%

Determination of Relationship between Higher Heating Value and Atomic Ratio of Hydrogen to Carbon in Spent Coffee Grounds by Hydrothermal Carbonization

et al. 2021

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This study was a preliminary investigation of solid recovered fuel production from spent coffee grounds using the hydrothermal carbonization (HTC) technique. The spent coffee grounds (SCGs) were subjected to HTC at 170 to 250 °C. The biochar was characterized by proximate analysis, ultimate analysis, capillary suction time, time to filter, suspended solids, and particle size distribution. The biochar yields decreased with increasing HTC temperature and time. However, the higher heating value (HHV) of biochar increased with the HTC temperature and time. The H/C slop relative to the O/C atomic rate of spent coffee grounds was 0.10 with low decarboxylation selectivity. Considering the HHV of biochar and dehydration capacity depend on ratio of H/C vs. O/C, the optimum reaction temperature of HTC was 200 °C, and the biochar from SCGs is an attractive biochar.

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“…For Case 1, the treatment method was a one-step chemical activation. The solid phase of the SAC was mixed with a solid phase of potassium hydroxide (KOH, Samchun Chemical, Seoul, South Korea), at a SAC/KOH weight ratio of 0.5 [ 19 , 20 , 21 ]. The samples were gradually heated at 5 °C/min until 750 °C, at which the temperature was maintained for 1 h. Subsequently, the samples were heated to 850 °C at a rate of 5 °C/min, and then held for 3 h. After chemical activation, the samples were washed with water three times and then neutralized.…”

Section: Methodsmentioning

confidence: 99%

“…An elemental analysis (EA) was conducted by following procedures described elsewhere using an elemental analyzer (Flash EA 1112, Thermo Scientific, Milan, Italy). The elemental contents of C, H, O, N, and S were determined [ 19 , 20 ].…”

Section: Methodsmentioning

confidence: 99%

Pre-Treatment Methods for Regeneration of Spent Activated Carbon

et al. 2020

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Spent activated carbon (SAC) usually exhibits a low specific surface area due to its high ash contents. In this study, pre-treatments, such as heat and acid treatments, were optimized to improve this feature. The heat pre-treatment did not reduce the ash content, nor did it increase the surface area. Because metallic ions adsorbed in SACs turn into ash upon the heat treatment. In the acid pre-treatment, the volatiles and fixed carbon were increased with decreasing ash contents. In this study, it was found that the surface area increase was correlated with the ratio between fixed carbon and ash. Among the pre-treatment methods, the combined heat and acid pre-treatment method highly increased the ratio, and therefore led to the surface area increase. Additionally, the acid pre-treatment was carried out using different types of acid (organic and inorganic acids) solutions to further improve the surface areas. The organic acid treatment caused a significant structural collapse compared to the inorganic acid treatment, decreasing the surface area. In particular, H3PO4 effectively removed ashes adsorbed on the activated carbon surface and regenerated the exhausted activated carbon. Both the heat and acid pre-treatments before chemical activation resulted in the positive effects such as strong desorption of pollutants and ashes within the internal structure of the activated carbon. Therefore, the regeneration introduced in this study is methodically the best method to regenerate SAC and maintain a stable structure.

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Influence of mixed methods on the surface area and gas products of activated carbon

Cited by 7 publications

References 38 publications

Straw-Derived Activated Carbon Decorated with Ag₃PO₄ for Organic Pollutant Removal by a Circular Degradation Mechanism: Adsorption and Photocatalysis

Straw-Derived Activated Carbon Decorated with Ag₃PO₄ for Organic Pollutant Removal by a Circular Degradation Mechanism: Adsorption and Photocatalysis

Determination of Relationship between Higher Heating Value and Atomic Ratio of Hydrogen to Carbon in Spent Coffee Grounds by Hydrothermal Carbonization

Pre-Treatment Methods for Regeneration of Spent Activated Carbon

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Influence of mixed methods on the surface area and gas products of activated carbon

Cited by 7 publications

References 38 publications

Straw-Derived Activated Carbon Decorated with Ag3PO4 for Organic Pollutant Removal by a Circular Degradation Mechanism: Adsorption and Photocatalysis

Straw-Derived Activated Carbon Decorated with Ag3PO4 for Organic Pollutant Removal by a Circular Degradation Mechanism: Adsorption and Photocatalysis

Determination of Relationship between Higher Heating Value and Atomic Ratio of Hydrogen to Carbon in Spent Coffee Grounds by Hydrothermal Carbonization

Pre-Treatment Methods for Regeneration of Spent Activated Carbon

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Straw-Derived Activated Carbon Decorated with Ag₃PO₄ for Organic Pollutant Removal by a Circular Degradation Mechanism: Adsorption and Photocatalysis

Straw-Derived Activated Carbon Decorated with Ag₃PO₄ for Organic Pollutant Removal by a Circular Degradation Mechanism: Adsorption and Photocatalysis