Adsorption of phenolic compounds on low-cost adsorbents: A review.

Adsorption of phenol and its derivatives from water using synthetic resins and low-cost natural adsorbents: a review

Adsorption characteristics of Congo Red on coal-based mesoporous activated carbon

The present work involves an investigation of the possible use of coal, residual coal, and residual coal treated with H3PO4 as a means of removal of phenol from wastewater. The study was realized using batch experiments, with synthetic wastewater having phenol concentration of 1000 ppm. Other low-cost adsorbents such as petroleum coke, coke breeze, rice husk, and rice husk char have also been used. The effect of system variables such as pH, contact time, and temperature has been investigated. The suitability of the Freundlich, Langmuir, and Redlich-Peterson adsorption models to the equilibrium data was investigated for each phenol-adsorbent system. The results showed that the equilibrium data for all the phenol-sorbent systems fitted the Redlich-Peterson model best. Kinetic modeling of removal of phenols was done using the Lagergren first-order rate expression. A series of column experiments were performed to determine the breakthrough curves.

Adsorption of phenols from wastewater.

Adsorption of Cd(II) ions from aqueous solutions using activated carbon prepared from olive stone by ZnCl2 activation.

The use of low rank coal-based adsorbents for the removal of nitrophenol from aqueous solution

Five low rank, coal-based adsorbents, i.e. coal, grus, two chars, and an activated carbon were used to adsorb a low molecular weight organic compound from aqueous solution. The rates of adsorption were found to conform to pseudo first order kinetics with good correlation (r2 greater than 0.996). This kinetic model was used to calculate pseudo first order rate constants (k1′ min −1) and relative rate constants (rate constant/unit mass of adsorbent, k1″ min−1 g−1) for the adsorption process. Rate properties have been explained in terms of both a diffusion and chemically controlled rate determining step. Rate constants for the five adsorbents vary as expected on the basis of their physical properties, that is slowest for grus (compressed coal) and fastest for the activated carbon.

© 1999 Society of Chemical Industry

A pseudo first order rate model for the adsorption of an organic adsorbate in aqueous solution

Char produced from low rank coal briquettes is potentially a cheap adsorbent suitable for the removal of trace levels of soluble organic compounds from water. In this study, briquette char produced from Victorian low rank coal was used to adsorb the organic compound p-nitrophenol (PNP) from aqueous solution, where nitrophenol is representative of low molecular weight adsorbates. Once concentrated on the adsorbent, attempts were made to remove the PNP by desorption and biodegradation. Desorbed PNP was degraded to some degree by three bacteria (Pseudomonas putida, Arthrobacter sp., and Moraxella sp.). The rates of PNP biodegradation by the three bacteria were followed, together with the corresponding rates of formation of the nitrite ion degradation product. Evidence is presented to indicate large microbial floc particle formation for both Pseudomonas putida and Arthrobacter leads to loss of nitrite ion by denitrification. Removal of PNP from the adsorbent by desorption/biodegradation was shown to be much faster than by desorption alone, but not all nitrophenol was removed from the adsorbent by the desorption/biodegradation process.

Pam H. Y. Li

Papers

The use of low rank coal-based adsorbents for the removal of nitrophenol from aqueous solution

A pseudo first order rate model for the adsorption of an organic adsorbate in aqueous solution

Bioregeneration involving a coal‐based adsorbent used for removing nitrophenol from water