The objective of this study was to investigate the application of advanced oxidation processes (AOPs) to the treatment of wastewaters contaminated with hydrocarbon oil. Three different oil-contaminated wastewaters were examined and compared: (i) a ‘real’ hydrocarbon wastewater collected from an oil refinery (Conoco-Phillips Whitegate refinery, County Cork, Ireland); (ii) a ‘real’ hydrocarbon wastewater collected from a car-wash facility located at a petroleum filling station; and (iii) a ‘synthetic’ hydrocarbon wastewater generated by emulsifying diesel oil and water. The AOPs investigated were Fe²⁺/H₂O₂ (Fenton's reagent), Fe²⁺/H₂O₂/UV (Photo-Fenton's reagent) which may be used as an alternative to, or in conjunction with, conventional treatment techniques. Laboratory-scale batch and continuous-flow experiments were undertaken. The photo-Fenton parametric concentrations to maximize COD removal were optimized: pH = 3, H₂O₂ = 400 mg/L, and Fe²⁺ = 40 mg/L. In the case of the oil-refinery wastewater, photo-Fenton treatment achieved approximately 50% COD removal and, when preceded by physicochemical treatment, the percentage removal increased to approximately 75%.

Nowadays, water scarcity is an identifiable problem facing society. However, as a result of modernization, water consumption is dramatically in increase although the water supply remains constant. Unfortunately every sector consumes water resulting in massive amounts of wastewater that requires treatment prior to their final disposal that still a challenge to the modern societies. Among the various technologies investigated, adsorption considered the most widely applied technology for safe environmental remediation. In this regard, the term of green adsorbents is introduced that is meant the low-cost materials originated from waste, i.e., agriculture waste to be valuable adsorbents. Thus, extensive list of different adsorbents from natural, industrial waste, agriculture bio-products or modified materials have been applied for the elimination of various contaminants from aqueous matrix are compiled here as a demanding area since it has double benefits as an industrial ecology approach. Also, this article discusses the basic principles of adsorption process including the adsorption isotherm and kinetic models. Although numerous review articles are dealing with low-cost adsorption performances, there is insufficient information on the emerging pollutants elimination. The major focus of this work is highlighting the research on the application of the low-cost adsorbents on the emerging pollutants, namely, pharmaceuticals, pesticides, personal care products and perfluorinated compounds. Scattered information on using various adsorbents are provided information in adsorbing emerging pollutants uptake reached to 920 mg/g. The main parameters that affect the adsorption process and the economic prospective is also discussed. Desorption and recycling scenario is concluded and desorption efficiency could reach to 99%. Finally, the future development of further research and few suggestions are also prospected. Graphical Abstract

Naturally abundant lignocellulosic material recovered from sugarcane industry has revealed a potential adsorbent for a textile dye uptake. In this work, bagasse is soaked with alkali then treated with sulphuric acid to produce cellulose fibres. X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) were used to characterise such adsorbent. SEM pictures explained that the chemically treated bagasse adsorbent has a micro-fibrous structure that increases the adsorption capacity. The experimental adsorption results and the characterisation data explore the prepared adsorbents from pure sugarcane bagasse (BG), chemically treated (BGT) or chemically and thermally treated (BGT500) are successfully used to remove Procion Blue (PB) dye from aqueous media. The highest dye removal was corresponding to 98.5% when BGT adsorbent was applied. Freundlich isotherm and pseudo-second order models are well described Procion Blue adsorption onto bagasse. The thermodynamic data, i.e. ΔG°, ΔH° and ΔS° illustrated the spontaneous and exothermic nature of the physical adsorption process. This investigation suggested that bagasse residue could be proposed as a low-cost adsorbent with a high adsorption capacity value for textile dye effluent removal.