Heavy metals like arsenic, copper, cadmium, chromium, nickel, zinc, lead, and mercury are major pollutants of fresh water reservoirs because of their toxic, non-biodegradable, and persistent nature. The industrial growth is the major source of heavy metals introducing such pollutants into different segments of the environment including air, water, soil, and biosphere. Heavy metals are easily absorbed by fishes and vegetables due to their high solubility in the aquatic environments. Hence, they may accumulate in the human body by means of the food chain. Various methods have been developed and used for water and wastewater treatment to decrease heavy metal concentrations. These technologies include membrane filtration, ion-exchange, adsorption, chemical precipitation, nanotechnology treatments, electrochemical and advanced oxidation processes. In this review, the methods as well as their mechanisms and efficiency are discussed.

Removal of Heavy Metals from Industrial Wastewaters: A Review

TiO2 photocatalyst for water treatment applications

Electrocoagulation process in water treatment: A review of electrocoagulation modeling approaches

Electrocoagulation and advanced electrocoagulation processes: A general review about the fundamentals, emerging applications and its association with other technologies

The nitrogen donor ligand was functionalized with polarable mesoporous silica as composite adsorbent, by a cost-effective and environmentally friendly procedure, for highly selective copper (Cu(II)) ions detection and removal from water. The nitrogen donor ligand of N , N (octane-1,8-diylidene)di(2-hydroxy-3,5-dimethylaniline) was synthesized to be specific to Cu(II) ions. The composite adsorbent permitted fast and specific Cu(II) ions capturing via colorimetric naked-eye detection based on stable complexation [Cu(II)–ligand] n + mechanism. The effect of pH value, interferential metal ions, initial Cu(II) concentration, and contact time on adsorption capability were investigated systematically. The adsorbent was selective toward Cu(II) as shown by a light yellow to green color change. This was characterized by UV–vis spectroscopy and the color change was observed for the visual detection of Cu(II) ions. The ions selectivity of the adsorbent toward Cu(II) was determined by changes in UV–vis reflectance spectra. However, the presence of competing ions showed no interference for the detection of Cu(II) ion by the composite adsorbent. The results demonstrated that the composite adsorbent exhibited excellent sorption performance for Cu(II) ions. The low detection limit and sorption capacity of the adsorbent were 0.10 μg/L and 200.80 mg/g, respectively. The adsorbed Cu(II) was eluted with suitable eluent and simultaneously regenerated into the initial form for next operation without significant deterioration in its nanostructure case cavities. The data also confirmed that the adsorbent is a cost-effective and environmentally friendly procedure for Cu(II) treatment. Therefore, the composite adsorbent can be considered as a potential adsorbent for Cu(II) ions monitoring and removal from wastewater.

M. Marchesiello

Papers

Removal of copper, zinc and nickel present in natural water containing Ca2+ and HCO3- ions by electrocoagulation