Abatement of organic pollutants using fly ash based adsorbents

Abstract

The presence of organic pollutants in the environment is of major concern because of their toxicity, bio-accumulating tendency, threat to human life and the environment. It is a well-known fact that, these pollutants can damage nerves, liver, and bones and could also block functional groups of essential enzymes. Conventional methods for removing dissolved pollutants include chemical precipitation, chemical oxidation or reduction, filtration, ion-exchange, electrochemical treatment, application of membrane technology, evaporation recovery and biological treatment. Although all the pollutant treatment techniques can be employed, they have their inherent advantages and limitations. Among all these methods, adsorption process is considered better than other methods because of convenience, easy operation and simplicity of design. A fundamentally important characteristic of good adsorbents is their high porosity and consequent larger surface area with more specific adsorption sites. This paper presents a review of adsorption of different pollutants using activated carbon prepared from fly ash sources and the attendant environmental implications. Also, the ways of overcoming barriers to fly ash utilization together with regeneration studies are also discussed.

Sorption studies of methyl red dye removal using lemon grass (Cymbopogon citratus)

“…Since last decades, many conventional techniques have been employed to decontaminate dyes from aqueous solution. Examples are chemical, biological and physiochemical methods [12][13][14][15][16][17][18][19][20][21][22][23][24][25] . Dyes are known to be resistant to biological degradation methods and their removal by conventional physicochemical techniques are inefficient [4,[26][27][28] .…”

Rhodamine B dye sequestration using Gmelina aborea leaf powder

“…Pollution emanating from dye effluents has become a serious environmental problem in the last decade owing to the increasing and fast growing usage of dyes in different applications. Some dyes are resistance to fading even on exposing to light, water and various chemicals [1,2,3]. Dyes are chemically and/or thermally stable.…”

“…Therefore, due to their harmful effects to both human and aquatic life, the removal of these colors from aqueous effluents become problematic because it poses a serious ecological damage due to its ability to extend to agricultural farm lands and water bodies. Therefore, dye effluents should not be directly discharge into the water bodies [1,3,9,10,11]. The treatment of dyes becomes imperative since a concentration as low as 1.0 mg/L in drinking water can impart intense color to the water and make it unsuitable for human consumption [3].…”

“…Also large volumes of water are required by textile industries in their operations, which in turn lead to the release of large volumes of effluents [3,4]. The distinctiveness in the composition of wastewater(s) from textile industries are such that they non-biodegradable and containing numerous dye materials [1,4,6,16,17]. This makes treatment of contaminated water demanding, since the colour tends to reoccur even after the removal process using conventional methods [18,19,20,21,22].…”

Functionalized coconut husks for rhodamine-B dye sequestration

“…Exploring this sustainable and eco-friendly adsorbent offers numerous usages for future industrial scale-up applications (Bello et al 2017a;Ojedokun and Bello 2017). The costs of ACs derived from biomaterials and agricultural wastes are realistically lower in comparison with CACs (Ahmad et al 2016;Adegoke et al 2017;Bello et al 2017a, c). In this study and for the first time, coconut husk was modified using orthophosphoric acid and its capability to remove rhodamine-B dye from simulated water was tested.…”