A general kinetic model for adsorption: Theoretical analysis and modeling

In the present work, the potential of citrus limetta peel (CLP) as a low cost adsorbent for the removal of Methylene blue (MB) dye was investigated. Batch adsorption studies were conducted to find out how adsorption was affected by various factors like contact time, initial dye concentration, adsorbent dosage, pH and temperature. The experimental data was analysed in the light of Langmuir, Freundlich and Temkin isotherm models. The data was found to be best represented by Langmuir adsorption isotherm with maximum adsorption capacity for monolayer coverage was found to be 227.3 mg/g. The data were analysed in the light of different available kinetic models and was observed to be best followed pseudo-second order kinetics. Desorption of MB-loaded CLP was studied with various desorbing agents and HCl was found to be most effective desorbing agent among HCl, NaOH, NaCl, CH3COOH and deionised doubly distilled water (DDDW). Results suggest that CLP is a very effective low cost adsorbent for the removal of dyes from wastewater.

Removal of methylene blue dye from artificially contaminated water using citrus limetta peel waste as a very low cost adsorbent

Derivation of Pseudo-First-Order, Pseudo-Second-Order and Modified Pseudo-First-Order Rate Equations from Langmuir and Freundlich isotherms for adsorption

Activated carbon (MTLAC) and sulfonic acid modified activated carbon (MTLAC-SA) were prepared from a low cost agricultural waste material matured tea leaf (MTL). BET surface area of MTLAC and MTLAC-SA was found to be 1313.4 m2/g and 1169.3 m2/g respectively. Synthesized materials were applied for adsorption of both anionic and cationic dyes. Rhodamine B (RhB), methylene blue (MB), brilliant green (BG), crystal violet (CV) and orange G (OG) were taken as the model dye. After modification, the activated carbon showed enhanced adsorption capacity for adsorption of cationic dyes. The effect of various parameters such as pH, initial dye concentration, adsorbent dose, ionic strength on adsorption process was investigated. A slight increase in adsorption capacity was observed with increase in concentration of existing ion. The equilibrium adsorption data were best described by Langmuir model. The maximum adsorption capacity for RhB and OG using MTLAC-SA (MTLAC) was found to be 757.6 (398.4) mg/g and 105.7 (318.5) mg/g respectively. The adsorption kinetics was best fitted with pseudo second order kinetic model. The thermodynamic study illustrated that the adsorption process is endothermic and spontaneous in nature.

Enhanced adsorption of cationic dyes using sulfonic acid modified activated carbon

Wastewater treatment is still a critical issue all over the world. Among examined methods for the decontamination of wastewaters, adsorption is a promising, cheap, environmentally friendly and efficient procedure. There are various types of adsorbents that have been used to remove different pollutants such as agricultural waste, compost, nanomaterials, algae, etc., Chitin (poly-β-(1,4)-N-acetyl-d-glucosamine) is the second most abundant natural biopolymer and it has attracted scientific attention as an inexpensive adsorbent for toxic metals. This review article provides information about the use of chitin as an adsorbent. A list of chitin adsorbents with maximum adsorption capacity and the best isotherm and kinetic fitting models are provided. Moreover, thermodynamic studies, regeneration studies, the mechanism of adsorption and the experimental conditions are also discussed in depth.

https://www.mdpi.com/1422-0067/18/1/114/pdf

Chitin Adsorbents for Toxic Metals: A Review

Kinetics, equilibrium studies and thermodynamics of methylene blue adsorption on Ephedra strobilacea saw dust and modified using phosphoric acid and zinc chloride

Mahdi Shahivand

Papers

Kinetics, equilibrium studies and thermodynamics of methylene blue adsorption on Ephedra strobilacea saw dust and modified using phosphoric acid and zinc chloride