The rapid increase in toxic dye wastewater generated from various industries remains a severe public health issue and prime environmental protection concern, posing a major challenge to existing conventional water treatment systems. Consequently, various physicochemical and biological treatment processes have been studied, which exhibit varying removal abilities depending on their experimental constraints. Among them, adsorption is considered to be the most efficient due to its high removal efficiency, easy operation, cost-effectiveness, and recyclability of the adsorbents. Considering this, the present review article focused on presenting a comprehensive summary of the various types of adsorbents such as commercial activated carbon, metal oxide-based, carbon-based, metal–organic framework, and polymer-based adsorbents used in dye remediation of contaminated water. The effects of several critical factors such as initial dye concentration, solution pH, temperature, and adsorbent dose on the dye adsorption performance are also described. In addition, the adsorption mechanisms responsible for dye removal are explained based on electrostatic attraction, ion exchange, surface complexation, and π–π interactions. Finally, critiques, future perspectives, and a summary of the present article are given. Various adsorbents such as carbon-based materials, metal oxides, bio-adsorbents, and polymer-based materials, have been shown to be efficient for the removal of dye pollutants from wastewater. Thus, it is anticipated that dye removal by adsorption can provide a feasible solution for the treatment of dye-laden water.

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Recent advances on the removal of dyes from wastewater using various adsorbents: A critical review

Environmental pollution, particularly from heavy metal ions in the wastewater, is one of the most serious concerns of the world. In the pursuit of remedial action, various conventional methods such...

Adsorption of heavy metal ions by various low-cost adsorbents: a review

Metallic species mobilized and released into the environment by the technological activities of human tend to persist indefinitely, circulating and eventually accumulating throughout the food chain, thus posing a serious threat to the environment, animals and humans. It is essential to realize that the metal is only removed from solution when it is appropriately immobilized. Apart from slow natural process of metal mineralization, ultimate removal is attained only when the metal becomes concentrated to the point that it can be either returned to the process or resold. The metallic pollutants can be sorbed by biosorbant material. The mechanism of biosorption is complex, mainly ion exchange, chelation, adsorption by physical forces, entrapment in inter and intrafibrilliar capillaries and spaces of the structural polysaccharide network as a result of the concentration gradient and diffusion through cell walls and membranes. Due to the extensive research and significant economic benefits of biosorption, some new biosorbant resources are poised for commercial exploitation.

Biosorption of Heavy Metals: A Review

Application of adsorption process for effective removal of emerging contaminants from water and wastewater.

A review on magnetic sensors for monitoring of hazardous pollutants in water resources

Transesterification of waste edible oils to biodiesel using calcium oxide@magnesium oxide nanocatalyst.

In this investigation, bentonite clay (BC) and bentonite clay@MnFe2O4 composite (BCMFC) were applied as efficient adsorbents for adsorbing Cr(III) and Cr(VI) ions from aqueous media. Different analyses such as FTIR, SEM, EDX, Map, BET, and XRD were used to characterize the adsorbents. The results showed that the removal efficiency of Cr(III) and Cr(VI) using BC were found to be 95.21 and 95.74%, while the corresponding values to the BCMFC were 97.37 and 98.65%, respectively. Also, the equilibrium and kinetic studies showed that the Freundlich isotherm model and the quasi-second-order kinetic model could better describe the equilibrium and kinetic behaviors of the adsorption process. The maximum adsorption capacity of the BC for the adsorption of Cr(III) and Cr(VI) ions were evaluated as 151.5 mg/g (25oC, pH 6, 90 min, and 1 g/L) and 161.3 mg/g (25oC, pH 3, 90 min, and 1 g/L), respectively, while the BCMFC showed the maximum capacities of 175.4 mg/g (25oC, pH 6, 60 min, and 1.5 g/L) and 178.6 mg/g (25oC, pH 3, 60 min, and 1.5 g/L) for Cr(III) and Cr(VI) ions, respectively, which were remarkable amounts. In addition, the thermodynamic study indicated that the adsorption process was physical, spontaneous, and exothermic. High removal efficiency, high chromium adsorption capacity, and low-cost magnetic adsorbent were significant features of the BCMFC for removal of Cr (III) and Cr (VI).

The role of bentonite clay and bentonite clay@MnFe2O4 composite and their physico-chemical properties on the removal of Cr(III) and Cr(VI) from aqueous media

https://iopscience.iop.org/article/10.1088/2053-1591/ab3ffb/pdf

Application of magnetic adsorbents for removal of heavy metals from wastewater: a review study

Chemically Modified CaO/Fe3O4 Nanocomposite by Sodium Dodecyl Sulfate for Cr(III) Removal from Water

The pollution caused by heavy metal ions in industrial wastewater is of a great concern. Applying effective and low-cost methods is an urgent need for treatment of polluted water and aqueous solutions. Biosorption have received the most attention among the various methods. It has become an alternative technique to conventional technologies due to low cost, simple operation and treatment for heavy metal recovery, and high selectivity. In recent years, sea material shells have been applied as one of the most cost-effective bio-adsorbents due to their special properties. They are environmentally friendly, low cost, and easy to access and have high adsorption capacity. The purpose of this review is to present the application of oyster shell, snail shell, and shrimp shell as low-cost and effective biosorbents for removal of noxious heavy metals from aqueous solutions. In addition, heavy metals, their sources, and ways to remediate them from waste streams and various factors affecting the biosorption process with sea materials shells are also reviewed. Moreover, a brief description and literature review of the equilibrium, kinetic, and thermodynamic behaviors of the heavy metal ion adsorption process on sea material shells have been studied. Finally, further applications of sea materials shell for waste effluents treatment are specially focused.

Sajad Tamjidi

Papers

Transesterification of waste edible oils to biodiesel using calcium oxide@magnesium oxide nanocatalyst.

The role of bentonite clay and bentonite clay@MnFe2O4 composite and their physico-chemical properties on the removal of Cr(III) and Cr(VI) from aqueous media

Application of magnetic adsorbents for removal of heavy metals from wastewater: a review study

Chemically Modified CaO/Fe3O4 Nanocomposite by Sodium Dodecyl Sulfate for Cr(III) Removal from Water

A review of the application of sea material shells as low cost and effective bio-adsorbent for removal of heavy metals from wastewater