The increasing demand for high-performance activated carbon necessitates applying sustainable and cost-effective production methods. This study explores the use of biochar derived from renewable biomass. The primary feedstock for biochar consisted of woody residues from composting, along with pre-dried sunflower seed shells that had a moisture content of around 10% as a precursor for the production of activated carbon. The process started with carbonization followed by potassium hydroxide (KOH) activation. Key parameters such as the impregnation ratio, temperature, and activation time were optimized to enhance the physicochemical properties of the activated carbon. Under optimized conditions, namely a KOH-to-biochar impregnation ratio of 3:1, an activation temperature of 800 °C, and an activation duration of 5 h, the yield of activated carbon was 58% and the specific surface area was 498 m²/g. A significant enhancement in surface area, with a maximum value of 709 m²/g, was achieved after increasing the time to 24 h of activation. Differential Scanning Calorimetry (DSC) analysis was applied to evaluate the CO₂ adsorption performance of both biochar and activated biochar at 30 °C, demonstrating a 30% improvement in adsorption efficiency following activation. This study underscores the potential of biochar as a renewable and sustainable precursor for the production of high-performance activated carbon. This study underscores the potential of biochar derived from agro residue as a source for the production of high-performance activated carbon. The findings contribute to the advancement of environmentally friendly production technologies and highlight the potential applicability of biochar-derived activated carbon in gas adsorption and environmental remediation.

The increasing demand for high-performance activated carbon necessitates applying sustainable and cost-effective production methods. This study explores the use of biochar, derived from renewable biomass. The primary feedstock for biochar consisted of woody residues from composting, along with pre-dried sunflower seed shells that had a moisture content of around 10% as a precursor for the production of activated carbon. The process started with carbonization followed by potassium hydroxide (KOH) activation, key parameters such as the impregnation ratio, temperature, and activation time were optimized to enhance the physicochemical properties of the activated carbon. Under optimized conditions, namely a KOH-to-biochar impregnation ratio of 3:1, an activation temperature of 800 °C, and an activation duration of 5 hours, the yield of activated carbon is 58% and a specific surface area of 498 m²/g. A significant enhancement in surface area, with a maximum value of 709 m²/g achieved after increasing the time to 24 hours of activation. differential scanning calorimetry (DSC) analysis was applied to evaluate the CO₂ adsorption performance of both biochar and activated biochar at 30°C, demonstrating a 30% improvement in adsorption efficiency following activation. This study underscores the potential of biochar as a renewable and sustainable precursor for the production of high-performance activated carbon. The findings contribute to the advancement of environmentally friendly production technologies and highlight the potential applicability of biochar-derived activated carbon in gas adsorption and environmental remediation.

Sugar production generates wastewater rich in dissolved solids and organic matter, and improper disposal poses severe environmental risks, exacerbates water scarcity, and creates regulatory challenges. Conventional treatment methods, such as evaporation and chemical precipitation, are energy-intensive and often ineffective at removing fine particulates and dissolved impurities. This study evaluates membrane-based separation as a sustainable alternative for water reclamation and sugar recovery from sugar industry effluents, focusing on replacing evaporation with membrane processes, ensuring high permeate quality, and mitigating membrane fouling. Cross-flow filtration experiments were conducted on a lab-scale membrane system at 70 °C to suppress microbial growth, comparing direct reverse osmosis (RO) of the raw effluent to an integrated ultrafiltration (UF)–RO process. Direct RO resulted in rapid membrane fouling. A tight UF (5 kDa) pre-treatment before RO significantly mitigated fouling and improved performance, enabling 28% water recovery and 79% sugar recovery, maintaining permeate conductivity below 0.5 mS/cm, sustaining stable flux, and reducing membrane blocking. Additionally, the UF and RO membranes were tested via SEM, EDS, and FTIR to elucidate the fouling mechanisms.

The environmental impacts from fossil fuel use have accelerated the global transition to sustainable energy sources. Hydrogen has become a promising alternative due to its high energy density and clean combustion. However, hydrogen production streams are frequently contaminated with methane, which needs efficient, durable, and cost-effective purification technologies such as pressure swing adsorption (PSA). The present study provides a comparative evaluation of biomass-derived activated carbons and a commercial activated carbon for hydrogen–methane separation. High-surface-area activated carbons were synthesized from sustainable pine and birch precursors via chemical activation using potassium hydroxide (KOH, impregnation ratio 3:1) at 800 °C. Their dynamic adsorption performance was systematically assessed in a fixed-bed setup under a PSA system operating at pressures of 25, 35, and 50 bar, using a of hydrogen–methane gas mixture, where methane feed concentrations ranging from 10 to 30 vol%. This work focuses on the behavior of the adsorbent material and does not constitute a complete PSA process evaluation. The biomass-derived activated carbons showed well-developed textural characteristics, with specific surface areas up to 1416 m² g⁻¹, which exceeded that of the commercial reference material (1023 m² g⁻¹). This improved pore structure was reflected in their adsorption behavior at an operating pressure of 50 bar; the birch-derived carbon achieved a methane uptake of 10.5 mol kg⁻¹, more than twice the capacity of 5.30 mol kg⁻¹ measured for the commercial adsorbent. Beyond initial adsorption capacity, the study emphasizes operational durability and reusability. Cyclic adsorption–desorption experiments, supported by Raman spectroscopy, revealed pronounced structural changes in the commercial activated carbon under repeated operational stress, as indicated by an increase in the I_D/I_G ratio from 1.08 to 1.24. In contrast, the biomass-derived activated carbons preserved their morphological integrity and adsorption efficiency over successive cycles. These findings demonstrate that pine- and birch-derived activated carbons are not only sustainable alternatives but also operationally stable adsorbents capable for hydrogen purification processes.

The environmental impacts from fossil fuel use have accelerated the global transition to sustainable energy sources. Hydrogen has become a promising alternative due to its high energy density and clean combustion. However, hydrogen production streams are frequently contaminated with methane, which needs efficient, durable, and cost-effective purification technologies such as Pressure Swing Adsorption (PSA). The present study provides a comparative evaluation of biomass-derived activated carbons and a commercial activated carbon for hydrogen–methane separation. High surface-area activated carbons were synthesized from sustainable pine and birch precursors via chemical activation using potassium hydroxide (KOH, impregnation ra-tio 3:1) at 800 °C. Their adsorption performance was systematically assessed in a fixed-bed PSA system operating at pressures of 25, 35, and 50 bar, with a gas mixture of hydrogen-methane, where methane feed concentrations was ranging from 10 to 30 vol%. The biomass-derived activated carbons showed well-developed textural characteristics, with specific surface areas up to 1416 m² g⁻¹, exceeding that of the commercial reference material (1023 m² g⁻¹). This improved pore structure was reflected in their adsorption behavior at an operating pressure of 50 bar, the birch-derived carbon achieved a methane uptake of 10.5 mol kg⁻¹, more than twice the capacity measured for the commercial adsorbent of 5.30 mol kg⁻¹. Beyond initial adsorption capacity, the study emphasizes operational durability and reusability. Cyclic adsorption–desorption experiments, supported by Raman spectroscopy, revealed pronounced structural degradation in the commercial activated carbon under repeated operational stress, as indicated by an increase in the ID/IG ratio from 1.08 to 1.24. In contrast, the biomass-derived activated carbons preserved their morphological integrity and adsorption efficiency over successive cycles. These findings demonstrate that pine- and birch-derived activated carbons are not only sustainable alternatives but also operationally stable adsorbents capable for hydrogen purification processes.

Sugar production generates wastewater rich in dissolved solids and organic matter, and improper disposal poses severe environmental risks, exacerbates water scarcity, and creates regulatory challenges. Conventional treatment methods, such as evaporation and chemical precipitation, are energy-intensive and often ineffective at removing fine particulates and dissolved impurities. This study evaluates membrane-based separation as a sustainable alternative for water reclamation and sugar recovery from sugar industry effluents, focusing on replacing evaporation with membrane processes, ensuring high permeate quality, and mitigating membrane fouling. Cross-flow filtration experiments were conducted on a lab-scale membrane system at 70 °C to suppress microbial growth, comparing direct reverse osmosis (RO) of the raw effluent to an integrated ultrafiltration (UF)–RO process. Direct RO resulted in rapid membrane fouling, which was characterized via SEM, EDS, and FTIR to elucidate the fouling mechanisms. A tight UF (5 kDa) pre-treatment before RO significantly mitigated fouling and improved performance, enabling 75 % water recovery, maintaining permeate conductivity below 0.5 mS/cm, sustaining stable flux, and reducing membrane blocking.