Industrial, agricultural, and domestic activities of humans have affected the environmental system, resulting in drastic problems such as global warming and the generation of wastewater containing high levels of pollutants. As water of good quality is a precious commodity and available in limited amounts, it has become highly imperative to treat wastewater for removal of pollutants. In addition, the rapid modernization of society has also led to the generation of huge amount of materials of little value that have no fruitful use. Such materials are generally considered as waste, and their disposal is a problem. Also, there are some materials that are available in nature that have little or no use. The utilization of all such materials as low-cost adsorbents for the treatment of wastewater may make them of some value. An effort has been made to give a brief idea of an approach to wastewater treatment, particularly discussing and highlighting in brief the low-cost alternative adsorbents with a view to utilizing these waste/low-cost materials.

Low-Cost Adsorbents: Growing Approach to Wastewater Treatment—a Review

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

Adsorption of phenol by bentonite.

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.

The role of activated charcoal in plant tissue culture.

An experimental investigation of the effects of pH and three inorganic salts (KCl, KI, and NaCl) on the adsorption isotherms of phenol (from a dilute aqueous solution) on activated charcoal was conducted. Each salt was studied at three different concentrations, i.e., 0.1, 0.001, and 0.005 M. The effect of pH (in the pH range 3 to 11) in the presence of KI, KCl, and NaCl was also investigated. The concentration of phenol in the aqueous systems studied ranged from 10 to 200 ppm. The temperature effect was also studied, and the resulting experimental equilibrium isotherms at 30, 40, and 55°C are well represented by Freundlich, Langmuir, and Redlich—Paterson isotherms. The relevant parameters for these isotherms are presented.

Effects of pH and Inorganic Salts on the Adsorption of Phenol from Aqueous Systems on Activated Decolorizing Charcoal

To evaluate its ability to remove phenol from aqueous solution, Jordanian “spent” oil shale, an abundant natural resource, has been used in an experimental adsorption study. Equilibrium of the system has been determined at three temperatures: 30, 40, and 55C. The resulting experimental equilibrium isotherms are well represented by Frendlich, Langmuir, and Redlich-Peterson isotherms. The relevant parameters for these isotherms, as regressed from the experimental equilibrium data, are presented. Effects of solution pH (in the range of 3–11), in addition to effects of three inorganic salts (KI, KCl, and NaCl, each at 0.1, 0.01, and 0.005 M), on the equilibrium isotherms have been experimentally investigated. The effects of pH in the presence of KI and NaCl were also investigated for a possible interaction between salts and solution pH. The initial concentration of phenol in the aqueous system studied ranges from 10 to 200 ppm. Experimental results show that while an acidic solution has no effect on ...

Naser M. Al-Dhoon

Papers

Effects of pH and Inorganic Salts on the Adsorption of Phenol from Aqueous Systems on Activated Decolorizing Charcoal

Adsorption of Phenol from Aqueous Systems onto Spent Oil Shale