Photocatalytic degradation of tetracycline in aqueous systems under visible light irridiation using needle-like SnO2 nanoparticles anchored on exfoliated g-C3N4

Background Pharmaceuticals is one of the groups of contaminants of emerging concern that are resistant to decomposition or removal by most of the existing water and wastewater treatment procedures, hence the need to develop techniques to facilitate the removals of this group of organic contaminants from water systems. In this study, needle-like SnO2 nanoparticles was synthesised and loaded on exfoliated g-C3N4 nanosheet through a hydrothermal method, for use as sensitive visible light induce-photocatalyst for the decomposition of tetracycline in aqueous systems. The synthesised composites was characterized and analysed for the nature of the heterojunction between the SnO2 nanoparticle and g-C3N4 nanosheet using microscopic and spectroscopic techniques. Results The composites were of improved surface properties and enhanced visible-light absorption. The synthesised SnO2/g-C3N4 nanocomposites with various amounts of SnO2 (10–50 mg), employed in the degradation of tetracycline under visible light irradiation, were of good degradation efficiency. The degradation efficiencies of tetracycline by 1 wt.%, 2 wt.%, 3 wt.% and 5 wt.% SnO2/g-C3N4 photocatalyst were 81.54%, 90.57%, 95.90% and 92.15% as compared to g-C3N4 and SnO2 with 40.92% and 51.32% degradation efficiencies. The synergistic interaction between the needle-like SnO2 and exfoliated g-C3N4 nanosheet promoted the separation of photogenerated electron holes pairs, which enhanced their migration rate between SnO2 and g-C3N4 heterojunction, thereby facilitating the degradation of tetracycline. The ·O2− was noted to be the major reactive species in the photocatalytic of the 3 wt.% SnO2/g-C3N4 nanocomposite. Conclusion The fabricated SnO2 nanoparticles anchored on exfoliated g-C3N4 showed good performance for the decomposition of tetracycline in water, with possible application on other pharmaceuticals having same moiety (similar chemical structures).

Application of Natural Coagulants for Pharmaceutical Removal from Water and Wastewater: A Review

Pharmaceutical contamination threatens both humans and the environment, and several technologies have been adapted for the removal of pharmaceuticals. The coagulation-flocculation process demonstrates a feasible solution for pharmaceutical removal. However, the chemical coagulation process has its drawbacks, such as excessive and toxic sludge production and high production cost. To overcome these shortcomings, the feasibility of natural-based coagulants, due to their biodegradability, safety, and availability, has been investigated by several researchers. This review presented the recent advances of using natural coagulants for pharmaceutical compound removal from aqueous solutions. The main mechanisms of natural coagulants for pharmaceutical removal from water and wastewater are charge neutralization and polymer bridges. Natural coagulants extracted from plants are more commonly investigated than those extracted from animals due to their affordability. Natural coagulants are competitive in terms of their performance and environmental sustainability. Developing a reliable extraction method is required, and therefore further investigation is essential to obtain a complete insight regarding the performance and the effect of environmental factors during pharmaceutical removal by natural coagulants. Finally, the indirect application of natural coagulants is an essential step for implementing green water and wastewater treatment technologies.

Applications of Nano-Zeolite in Wastewater Treatment: An Overview

Nano-zeolite is an innovative class of materials that received recognition for its potential use in water and tertiary wastewater treatment. These applications include ion-exchange/sorption, photo-degradation, and membrane separation. The aim of this work is to summarize and analyze the current knowledge about the utilization of nano-zeolite in these applications, identify the gaps in this field, and highlight the challenges that face the wide scale applications of these materials. Within this context, an introduction to water quality, water and wastewater treatment, utilization of zeolite in contaminant removal from water was addressed and linked to its structure and the advances in zeolite preparation techniques were overviewed. To have insights into the trends of the scientific interest in this field, an in-depth analysis of the variation in annual research distribution over the last decade was performed for each application. This analysis covered the research that addressed the potential use of both zeolites and nano-zeolites. For each application, the characterization, experimental testing schemes, and theoretical analysis methodologies were overviewed. The results of the most advanced research were collected, summarized, and analyzed to allow an easy visualization and comparison of these research results. Finally, the gaps and challenges that face these applications are concluded.

Synthesis of composite nanostructure natural ZrO2 and magnetite particles (Fe3O4@ZrO2) and study of its lead ion adsorption efficiency

The potential of zircon minerals in Indonesia, especially in Central Kalimantan, has not been adequately explored and developed into valuable materials with high technical and economic value and environmentally friendly. This research has the potential to be processed and formed into advanced materials, seeing its high potential as an excellent adsorbent for anions/cations in water treatment and industrial wastewater. This research aims to develop raw zircon minerals into zircon oxides, which will later be composited with magnetic nanoparticles. The zircon mineral processing is carried out using hydrothermal methods. It is known that the physical and mechanical characteristics are suitable to be developed by having good reusability and durability as advanced materials. The adsorbent characterizations of FTIR, SEM, and XRF analysis showed that the Fe3O4@ZrO2 had many different functional groups and a high specific surface area for adsorption processes. The Fe3O4@ZrO2 showed high adsorption uptake capacity and selectivity for the lead in the Sasirangan textiles wastewater. Therefore, the Fe3O4@ZrO2 have the potential to be used as an adsorbent in water and wastewater treatment.

Transformation of carbon dots by ultraviolet irradiation, ozonation, and chlorination processes: Kinetics and mechanisms

As a new carbon nanomaterial, carbon dots (CDs) with unique physicochemical and luminescent properties have wide-ranging applications. Once released into the water and wastewater treatment plants, CDs will undergo physicochemical...