A. Carmalin Sophia

Decolorization and degradation of H-acid and other dyes using ferrous–hydrogen peroxide system

In this study, advanced oxidation process utilizing Fentons reaction was investigated for the decolorization and degradation of two commercial dyes viz., Red M5B, Blue MR and H-acid, a dye intermediate used in chemical industries for the synthesis of direct, reactive and azo dyes. Effect of Fe2 +, H2O2, pH, and contact time on the degradation of the dyes was studied. Maximum color and COD removal was obtained for Red MSB, H-acid and Blue MR at 10-25 mg/l of Fe2+ dose and 400-500 mg/l of H2O2 dose at pH 3.0. The initial oxidation reaction was found to fit into first order rate kinetics and the rate of oxidation of H-acid was higher than the other dyes. Release of chloride and sulfate from the Fentons treated Red M5B dye and sulfate from H-acid and Blue MR indicates that the dye degradation proceeds through cleavage of the substituent group.

Application of graphene based materials for adsorption of pharmaceutical traces from water and wastewater- a review

AbstractTraces of pharmaceuticals have been classified as emerging pollutants due to their persistence in the aquatic ecosystem. There has been indiscriminate disposal of pharmaceutical waste from manufacturing processes, half used, expired antibiotics as a result of which, huge quantities of bacterial resistant antibiotic wastewater have been introduced into natural ecosystems. In addition, drugs that are not fully metabolized in the body may be excreted into the sewer system. Therefore, treatment of pharmaceutical wastewater is a global concern. A wide range of treatment methodologies have been developed to treat pharmaceutical wastewater viz., chemical oxidation, biodegradation, adsorption, liquid extraction, membrane techniques, etc. However, adsorption is a promising method for the removal of micropollutants because of its simple design, low-cost, high efficiency, etc. Research has shown that graphene materials can be used as photo-catalysts, adsorbents, and as disinfectants in water treatment. They ...

Removal of emerging contaminants from the environment by adsorption

Emerging contaminants (ECs) are pollutants of growing concern. They are mainly organic compounds such as: pesticides, pharmaceuticals and personal care products, hormones, plasticizers, food additives, wood preservatives, laundry detergents, surfactants, disinfectants, flame retardants, and other organic compounds that were found recently in natural wastewater stream generated by human and industrial activities. A majority of ECs does not have standard regulations and could lead to lethal effects on human and aquatic life even at small concentrations. The conventional primary and secondary water treatment plants do not remove or degrade these toxic pollutants efficiently and hence need cost effective tertiary treatment method. Adsorption is a promising method worldwide for EC removal since it is low initial cost for implementation, highly-efficient and has simple operating design. Research has shown that the application of different adsorbents such as, activated carbons(ACs), modified biochars (BCs), nanoadsorbents (carbon nanotubes and graphene), composite adsorbents, and other are being used for ECs removal from water and wastewater. The current review intends to investigate adsorption process as an efficient method for the treatment of ECs. The mechanism of adsorption has also been discussed.

Recent Developments in Adsorption of Dyes Using Graphene Based Nanomaterials

Dyes are frequently let out into the environment along with wastewater sans necessary treatment. Fast, cost-effective, scientific and suitable elimination of dyes from wastewaters has been an important problem for researchers. Adsorption technique is a robust, well studied, widely employed and promising water treatment method. In the last decade, nanocarbon based adsorbents have gained attention in water treatment. These adsorbents are usually produced from low cost substrate and are found to be highly efficient than other adsorbents. Recently, graphene based nanomaterials are widely used as adsorbents to sorb various toxic organic contaminants from aqueous solutions. It showed high efficiency due to its chemical stability, structure, surface area and surface functional groups. So graphene are called as ‘miracle material’. Recently nanographene composites are proven to be a likely adsorbent for eliminating contaminants from the industrial effluents. In this chapter, we have presented briefly the synthesis of graphene and its other variants viz., GO, rGO and nano graphene composites. This chapter presents a small introduction to adsorption principles and adsorption isotherms. It explains the synthesis and use of nano graphene materials for the remediation of dyes. It also consolidates the recent literature available for dye adsorption using graphene materials and its mechanism.