In the last few decades, pharmaceuticals, credited with saving millions of lives, have emerged as a new class of environmental contaminant. These compounds can have both chronic and acute harmful effects on natural flora and fauna. The presence of pharmaceutical contaminants in ground waters, surface waters (lakes, rivers, and streams), sea water, wastewater treatment plants (influents and effluents), soils, and sludges has been well doccumented. A range of methods including oxidation, photolysis, UV-degradation, nanofiltration, reverse osmosis, and adsorption has been used for their remediation from aqueous systems. Many methods have been commercially limited by toxic sludge generation, incomplete removal, high capital and operating costs, and the need for skilled operating and maintenance personnel. Adsorption technologies are a low-cost alternative, easily used in developing countries where there is a dearth of advanced technologies, skilled personnel, and available capital, and adsorption appears to be the most broadly feasible pharmaceutical removal method. Adsorption remediation methods are easily integrated with wastewater treatment plants (WWTPs). Herein, we have reviewed the literature (1990-2018) illustrating the rising environmental pharmaceutical contamination concerns as well as remediation efforts emphasizing adsorption.

Pharmaceuticals of Emerging Concern in Aquatic Systems: Chemistry, Occurrence, Effects, and Removal Methods.

There are number of water purification techniques but the adsorption is one of the most simplest, effective and economical method for wastewater purification. In this article a large number of solid adsorbents such as Natural adsorbents, Agricultural Wastes, Industrial wastes, Biomass, Nanoadsorbents: Carbon based nanomaterials, Nobel metal based nanomaterials, Metal oxide based nanomaterials, Spinel ferrite based nanomaterials, Nanocomposites, Dendritic polymers; Geopolymer cement have been discussed for the removal of different pollutants from waste water. Removal of Fluoride, Phosphate, Nitrate and Radionuclides from wastewater has also been reviewed in this article. Adsorption isotherm models, kinetic models, thermodynamic parameters and adsorption mechanism have also been discussed. The present article lists different type of adsorbents and reviews state-of-the-art of the removal of different pollutants from water. The efforts have been made to discuss the sources of contamination and toxicities of pollutants. Adsorption mechanisms responsible for pollutants removal by different adsorbents have been reviewed. Attempts have also been made to point out the advantages and drawbacks of adsorbents and the future research needs in the area of water purification by adsorbents.

Water purification by using Adsorbents: A Review

Use of surfactants for the remediation of contaminated soils: a review.

Organic compounds can interact with clay minerals by i) adsorption at the external surfaces, ii) adsorption at the external and internal surfaces, iii) by exchange of exchangeable ions at the external surfaces, iv) by exchange of exchangeable ions at the external and internal surfaces, and v) by grafting reactions with silanol and aluminol groups leading to covalent bonds. Kaolin minerals intercalate only are a limited number of compounds whereas the reactions of 2:1 clay minerals, in particular smectites and vermiculites, are very manifold. Special attention is given to the interaction with neutral organic molecules such as alcohols, fatty acids, amines, amino acids, aromatic compounds, macrocyclic compounds, and nuclein bases. The interaction with complexes and dyes also provides the basis of advanced applications of clay minerals. Binding of long chain alkylammonium ions is a fundamental reaction for hydrophobising clay mineral particles as needed in many applications. The interaction of clay minerals with polymers including proteins is not only an actual field of research but also of practical importance. Organo-clay minerals are used as effective adsorbents. As these materials also adsorb solvent molecules together with the adsorptive, the adsorption process must be considered as adsorption from binary solution which, therefore, is also described in this chapter.

Clay mineral-organic interactions

Adsorbents based on montmorillonite for contaminant removal from water: A review

Influence of heating on the solid acidity of montmorillonite: A combined study by DRIFT and Hammett indicators

Hydration of methane intercalated in Na-smectites with distinct layer charge: insights from molecular simulations.

Silica minerals, one of the most abundant mineral species on the earth, play important roles in geochemistry and environment processes. The diversity of the SiO4 tetrahedron polymerization style might result in the heterogeneity of the surface microstructures and properties of SiO2 polymorphs. The surface properties of two common crystalline SiO2 polymorphs, i.e., α-quartz and α-cristobalite, have been investigated by the surface site density measurement, batch methylene blue (MB) adsorption, and X-ray photoelectron spectroscopy (XPS). The Langmuir adsorption isotherms suggest the formation of monolayer MB on both α-quartz and α-cristobalite surfaces. The adsorption capacity of α-quartz toward MB is larger than that of α-cristobalite, which positively correlates with the density of surface site. XPS spectra reveal that the adsorption takes place between the nitrogen atom of the dimethylamino groups in MB and silanols on α-quartz and α-cristobalite surfaces. The O/Si atom ratio related with adsorption of α...

Surface Heterogeneity of SiO2 Polymorphs: An XPS Investigation of α-Quartz and α-Cristobalite

When clay minerals, notably smectites, intercalate organic cations, their interlayer surfaces change from hydrophilic to hydrophobic. The resultant intercalates, known as organo-clays (OCs), have a large affinity for hydrophobic organic contaminants (HOCs). Organo-clays are used as sorbents of HOCs in wastewater treatment and as sorptive barriers in landfill liners. The structural and sorptive characteristics of OCs with respect to HOCs have been studied extensively, and a large volume of literature has accumulated over the past few decades. The interactions of OCs with HOCs and the various approaches to improving the sorption capacity of OCs are reviewed here, with particular reference to the application of novel analytical techniques, such as molecular modeling, to characterizing the OC–HOC interaction.

Qing Zhou

Papers

Adsorbents based on montmorillonite for contaminant removal from water: A review

Influence of heating on the solid acidity of montmorillonite: A combined study by DRIFT and Hammett indicators

Hydration of methane intercalated in Na-smectites with distinct layer charge: insights from molecular simulations.

Surface Heterogeneity of SiO2 Polymorphs: An XPS Investigation of α-Quartz and α-Cristobalite

Organo-clays as sorbents of hydrophobic organic contaminants: sorptive characteristics and approaches to enhancing sorption capacity