Search

Graphical abstract Highlights • Modification of ZnO with graphene oxide (GO) gives a highly effective photocatalyst for photodegradation of Triclosan. • The photoirradation is the best method to obtain ZnO/GO hybrid photocatalyst with low GO content and adequate perfromance. • The OG acts like an electron trap enhancing the photocatalytic performance. • The ZnO/GO photocatalyst is able to degrade Triclosan under visible light up to 47% of the initial concentration. Abstract Modification of ZnO nanoparticles with graphene oxide (GO) was carried out, and the obtained hybrid photocatalyst was used for the photodegradation of triclosan (TCS), which is an endocrine disrupting compound. Three different concentrations of GO were used to modify ZnO catalyst using the photoirradiation method and the resultant materials were characterised by SEM, TEM, Zeta Potential, FTIR, Raman, N 2 Physisorption, HPLC, XRD and UV–vis spectrophotometry in order to determine their physico-chemical and photocatalytic properties. Regarding the photocatalytic evaluation, the results of the photodegradation process for TCS showed that GO acts as a trap of electrons improving the performance of ZnO even at low TCS concentration (8 mg.L−1) under visible light radiation. The GO-modified composite that contains the highest GO concentration (0.5% w/w) was the material that showed the best photocatalytic performance under visible light degrading up to 45% of the initial concentration of TCS and showed a reaction rate constant two times higher than pristine zinc oxide. This study allowed us to propose the photocatalytic mechanism of ZnO/GO hybrid photocatalysts to degrade TCS. In addition, this research contributes to the understanding of the enhancement of the efficiency of ZnO/GO hybrids and contributes to obtaining a photoactive material with promising use under natural light radiation in an Advance Oxidation Process to eliminate endocrine-disrupting compounds such as triclosan. [ABSTRACT FROM AUTHOR]

Despite advances in technology and safety measures, accidental releases of crude oil and refined products into marine and freshwater environments remains a major environmental concern. To minimize the impacts of future spills on our aquatic ecosystems and human health, numerous studies have been refocused on the development of novel approaches to remove oil from water. An emerging low-cost, eco-friendly method is based on the use non-toxic and biodegradable cellulose-based sorbents for oil retrieval and recovery from water. Herein we seek to succinctly analyze the progress of cellulose-based materials developed to date in terms of their effectiveness as an oil sorbent and development potential into a commercial product for oil spill recovery operations. The results of the review highlight the potential use of cellulose nanocrystals and cellulose nanofibrils as sorbent materials with highly desirable properties for oil spills cleanup. With unique hydrophobic and oleophilic properties (in terms of oil selectivity) and physical and mechanical properties (high surface area and small pore size), cellulose-based sorbents may be an ideal alternative material for use in cleaning up oil spills. Combining both hydrophobic and magnetic properties by introduction of iron oxide nanoparticles offers high reusability and functionality, easy operation and facile separation of the cellulose-based sorbents; thus, it would offer a new approach against oil spills and fouling challenges. Furthermore, their reusability after oil uptake serves as additional steps to sustainability. Nevertheless, work is still required to determine and figure out the practical levels of utility of the cellulose-based sorbents on a commercial scale, facilitating the control and management of minor oil spills. [Display omitted] • Current state-of-the art of cellulose based materials for oil recovery. • Chemical modification promotes the oil sorption capacity and buoyancy properties. • Cellulose nanocrystals and nanofibrils hold great promise for oil spills recovery. • Cellulose complexation with magnetite allows a quick and efficient oil retrieval. • Cellulosic waste stands out as potential materials for obtaining cellulose. [ABSTRACT FROM AUTHOR]

The work focus to enhance the properties of xanthan gum (XG) by anchoring metal ions (Fe, Zr) and encapsulating inorganic matrix (M@XG-ZA). The fabricated nanocomposite was characterized by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), Fourier Transform Infrared Spectroscopy (FTIR), surface area (BET) and zeta potential analysis. The adsorption of Sc, Nd, Tm and Yb was investigated after screening of synthesized materials in detail to understand the influence of pH, contact time, temperature and initial REE (rare earth element) concentration both in single and multicomponent system via batch adsorption. The adsorption mechanism was verified by FTIR, SEM and elemental mapping. The SEM images of Zr@XG-ZA demonstrate scutes structure, which disappeared after adsorption of REEs. The maximum adsorption capacities were 132.30, 14.01, 18.15 and 25.73 mg/g for Sc, Nd, Tm and Yb, respectively. The adsorption efficiency over Zr@XG-ZA in multicomponent system was higher than single system and the REEs followed the order: Sc > Yb > Tm > Nd. The Zr@XG-ZA demonstrate good adsorption behavior for REEs up to five cycles and then it can be used as photocatalyst for the degradation of tetracycline. Thus, the work adds a new insight to design and preparation of efficient bifunctional adsorbents from sustainable materials for water purification. [ABSTRACT FROM AUTHOR]

Visible-light photocatalytic degradation of tetracycline was investigated by functional modified ZnIn 2 S 4 via anthraquinone-2-sulfonate (AQS) doped polypyrrole (PPy). The best photocatalytic activity of AQS/PPy-ZnIn 2 S 4 composite photocatalyst was obtained when the weight ratio of AQS/PPy versus ZnIn 2 S 4 was 1.0% and the molar ratio of PPy to AQS was 40. After 3.0 h photocatalytic reaction, more than 98% tetracycline was removed and almost 2.0 times higher of NPOC (non-purgeable organic carbon) removal rate was obtained compared with pure ZnIn 2 S 4 . Active species trapping experiments demonstrated that O 2 − played a major role rather than the OH and photogenerated holes. The AQS doped in PPy matrix behaved as electron acceptor-donor mediator which facilitated the formation of O 2 − . Two kinds of solid phase extraction (SPE) methods were developed before gas chromatography mass spectroscopy (GC–MS) analysis and eight intermediates were detected. The degradation of tetracycline originated from the photogenerated holes via loss of some functional groups and then aromatic ring was destroyed by the oxidation of active species O 2 − and OH via hydroxylation reaction. [ABSTRACT FROM AUTHOR]