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The disposal of wastewater containing silver is an environmental concern. Due to the toxicity of silver, treatment of such wastewater is necessary. Real wastewater contains a complex matrix of pollutants. The purpose of this paper is to study the adsorption behavior of silver in single and binary systems (with nickel) onto granular activated carbon.

The effect of silver ions concentration and the mass of adsorbent on the adsorption behavior were analyzed. Five two-parameter isotherms (Langmuir, Elovich, Freundlich, Dubinin–Radushkevich and Temkin) were applied to investigate the adsorption mechanism. Both linear and nonlinear regressions were tested for the first three isotherms. The experimental data were also fitted to Redlich–Petersons, Sips and Toth models.

A direct relationship between the initial silver ion concentration and its adsorption capacity was observed, whereas an inverse relationship between the adsorbent mass and the adsorption capacity was documented. The Langmuir model was found to best-fit the data indicating monolayer adsorption behavior. The maximum uptake was 2,500 mg/g in the single adsorption system. This value decreased to 909 mg/g in the binary system. The adsorption was found to have an exothermic chemical nature.

The study of the silver adsorption in a single system is inaccurate. Real wastewater contains a complex matrix of pollutants. This research gives a clear insight into the adsorption behavior in binary systems.

The aim of this study was to evaluate the environmental awareness among students in middle and high schools in an industrial city (Yanbu, Saudi Arabia).

A survey was distributed to 279 students in three schools of the city. Both perception of different environment issues and attitude towards the environment were assessed. Different sources of information about the environment were searched. Comparison of the degree of environmental awareness according to age and gender was investigated.

Results indicated girls to be more knowledgeable than boys. The results also showed that TV and internet are the most important sources of information about the environment.

This study can be important in identifying the level of environmental awareness among students in an industrial city and the different factors that affect this awareness.

To the author's knowledge, research studies investigating the environmental awareness of school students in the industrial areas in the Middle East are very few.