There is an increased global demand for activated carbon (AC) in application of water treatment and purification. Water pollutants that have exhibited a greater removal efficiency by AC included but not limited to heavy metals, pharmaceuticals, pesticides, natural organic matter, disinfection by-products, and microplastics. Granular activated carbon (GAC) is mostly used in aqueous solutions and adsorption columns for water treatment. Commercial AC is not only costly, but also obtained from non-renewable sources. This has prompted the search for alternative renewable materials for AC production. Biomass wastes present a great potential of such materials because of their availability and carbonaceous nature. This in turn can reduce on the adverse environmental effects caused by poor disposal of these wastes. The challenges associated with biomass waste based GAC are their low strength and attrition resistance which make them easily disintegrate under aqueous phase. This paper provides a comprehensive review on recent advances in production of biomass waste based GAC for water treatment and highlights future research directions. Production parameters such as granulation conditions, use of binders, carbonization, activation methods, and their effect on textural properties are discussed. Factors influencing the adsorption capacities of the derived GACs, adsorption models, adsorption mechanisms, and their regeneration potentials are reviewed. The literature reveals that biomass waste materials can produce GAC for use in water treatment with possibilities of being regenerated. Nonetheless, there is a need to explore 1) the effect of preparation pathways on the adsorptive properties of biomass derived GAC, 2) sustainable production of biomass derived GAC based on life cycle assessment and techno-economic analysis, and 3) adsorption mechanisms of GAC for removal of contaminants of emerging concerns such as microplastics and unregulated disinfection by-products.

Synthesis and application of Granular activated carbon from biomass waste materials for water treatment: A review

High surface area and mesoporous activated carbon from KOH-activated dragon fruit peels for methylene blue dye adsorption: Optimization and mechanism study

Adsorption isotherm models: A comprehensive and systematic review (2010-2020).

Adsorption isotherm models: A comprehensive and systematic review (2010−2020)

In this work, the date palm petiole was transformed into activated carbon implying sodium hydroxide as the activating agent. The carbon obtained was exerted for the adsorption of indigo carmine in batch and continuous mode. The properties of activated carbon were established. The effects of pH, adsorbent mass, contact time, initial concentration and temperature on the adsorption of indigo carmine were examined in batch mode. The models of Langmuir, Freundlich, Temkin and Dubinin-Radushkevich were used for modeling adsorption isotherms. The Langmuir model appears to be the most appropriate for describing the adsorption of indigo carmine. The adsorption mechanism was governed by the pseudo-second order model and can be explained by physisorption accompanied by chemisorption. From the thermodynamic point of view, the adsorption was spontaneous and exothermic. In continuous adsorption, The Bohart-Adams model fit perfectly to the initial part of the breakthrough curve ((Ct/C0)

Batch and continuous column adsorption of indigo carmine onto activated carbon derived from date palm petiole

In this study, for the first time, jamun seed derived activated carbon was used as an adsorbent for removal of fluoride from water. Activated carbon was prepared by KOH activation of jamun seed and subsequent pyrolysis at 900 °C. The fluoride sorption experiments were carried out under batch mode to optimize the various influencing parameters such as contact time (0–3 h), dosage of adsorbent (20–500 mg), initial fluoride concentration (2–20 mg L−1), temperature (298–308–318 K), and pH (2.5–10). The contact time and pH for maximum fluoride uptake were observed at 120 min and 2.5 respectively. Maximum adsorption capacity (3.65 mg g-1) of fluoride on activated carbon was found for 10 mg L−1 of initial fluoride concentration using 0.4 g L−1 adsorbent dosage. The equilibrium data were found to follow Dubinin-Radushkevich isotherm among the three applied isotherm models (Freundlich, Temkin, and Dubinin-Radushkevich) and pseudo-second-order kinetic mechanism with the rate constant of 0.036 g mg−1 min−1. Thermodynamic analysis revealed that the adsorption process was exothermic in nature. Performance of the prepared adsorbent was compared with other reported biomass derived activated carbons and it was observed that the proposed adsorbent is efficient in terms of its adsorption capacity. In addition to synthetic samples, field water samples collected from fluoride affected villages were also tested for adsorption experiments.

Shantanu Soni

Papers

Fluoride adsorption from aqueous solution using activated carbon obtained from KOH-treated jamun (Syzygium cumini) seed