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Dyes are an important class of organic pollutants and well known for their hazardous effects to the aquatic life in general and the human beings in particular. In order to reduce the negative effects of dye contaminated wastewater to the humans and the environment, the wastewater must be treated carefully before discharge into main streams. Advances in science and technology have led to the evolution of several techniques for the removal of dyes from industrial and domestic effluents. In this review, the more recent methods for the removal of dyes from water and wastewater have been discussed. Wastewater treatment techniques such as adsorption, oxidation, flocculation-coagulation, membrane filtration and biological treatment have been highlighted. Besides, efforts were made to review all the available techniques and recently published studies from 2010-2014. Furthermore, performances and special features of these technologies have been summarised. Advantages and limitations of each technique are also presented. Literature survey reveals that chemical oxidation, adsorption, and biological treatments have been the most frequently investigated techniques for dye removal over the past few years.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new virus in coronavirus family that causes coronavirus disease (COVID-19), emerges as a big threat to the human race. To date, there is no medicine and vaccine available for COVID-19 treatment. While the development of medicines and vaccines are essentially and urgently required, what is also extremely important is the repurposing of smart materials to design effective systems for combating COVID-19. Graphene and graphene-related materials (GRMs) exhibit extraordinary physicochemical, electrical, optical, antiviral, antimicrobial, and other fascinating properties that warrant them as potential candidates for designing and development of high-performance components and devices required for COVID-19 pandemic and other futuristic calamities. In this article, we discuss the potential of graphene and GRMs for healthcare applications and how they may contribute to fighting against COVID-19.

Adsorptive removal of toxic amaranth dye by alumina reinforced polystyrene (ARP) composite was studied as a function of contact time, pH, initial dye concentration, and temperature. The results indicated that adsorption was strongly dependent on pH and temperature of the dye solution. The adsorption was favored at low pH with the maximum removal at pH 2.0. Langmuir, Freundlich, Temkin, and DubininRadushkevich (D-R) models were used for the description of adsorption equilibrium data and the best interpretation for the experimental data was given by the D-R model. The adsorption kinetics was tested using pseudo first order, pseudo second order, Elovich, intraparticle, and film diffusion models and the removal by ARP followed a pseudo second order kinetics. Thermodynamic studies revealed that both adsorption and desorption was spontaneous and endothermic in nature. From the exhausted adsorbent, about 70 and 96% desorption was obtained with (99%) CH 3 OH and 0.1 M NaOH, respectively.

In this work, a polyaniline/iron oxide (PANIIO) composite was prepared and evaluated for its amido black 10B (AB10B) dye adsorption characteristics from aqueous solution. Adsorption equilibrium kinetic and thermodynamic experiments of AB10B onto PANIIO were studied in a batch system. The effects of solution pH, initial dye concentration, contact time, and temperature on the adsorption capacity of PANIIO for AB10B have been investigated. The pseudofirst-order and pseudosecond-order kinetic models were used to describe the kinetic data. It was found that adsorption kinetics followed the pseudosecond-order kinetic model at all of the studied temperatures. The Langmuir and Freundlich adsorption models were used for the mathematical description of adsorption equilibrium data, and the best fit was obtained using the Freundlich isotherm with an R 2 value of 0.9948. The change of Gibbs energy, enthalpy, and entropy of adsorption was also evaluated for the adsorption of AB10B onto PANIIO.