Efficient artificial mineralization route to decontaminate Arsenic(III) polluted water -the Tooeleite Way

Increasing exposure to arsenic (As) contaminated ground water is a great threat to humanity. Suitable technology for As immobilization and removal from water, especially for As(III) than As(V), is not available yet. However, it is known that As(III) is more toxic than As(V) and most groundwater aquifers, particularly the Gangetic basin in India, is alarmingly contaminated with it. In search of a viable solution here, we took a cue from the natural mineralization of Tooeleite, a mineral containing Fe(III) and As(III)ions, grown under acidic condition, in presence of SO42- ions. Complying to this natural process, we could grow and separate Tooeleite-like templates from Fe(III) and As(III) containing water at overall circumneutral pH and in absence of SO42- ions by using highly polar Zn-only ends of wurtzite ZnS nanorods as insoluble nano-acidic-surfaces. The central idea here is to exploit these insoluble nano-acidic-surfaces (called as INAS in the manuscript) as nucleation centres for Tooeleite growth while keeping the overall pH of the aqueous media neutral. Therefore, we propose a novel method of artificial mineralization of As(III) by mimicking a natural process at nanoscale

Large-scale aqueous synthesis of Cu(In,Ga)Se2nanoparticles for photocatalytic degradation of ciprofloxacin

Environmentally friendly synthesis of Cu(In,Ga)Se2 (CIGS) nanoparticles (NPs) is pivotal for producing sustainable photocatalytic compounds to be applied in the remediation of contaminants of emerging concern from water. To this end, we herein report an aqueous synthesis of CIGS NPs, followed by annealing, to give access to phasepure CIGS crystals with chalcopyrite structure and no signs of secondary phases. Morphological and compositional characterization revealed NPs with an average size of 10–35 nm and uniform distribution of Cu, In, Ga, and Se elements. In addition, the first aqueous large-scale synthesis of CIGS NPs is developed by up-scaling the synthesis procedure, resulting in 5 g of highly crystalline nanoparticles exhibiting an ideal optical band gap of 1.14 eV. The as-synthesized NPs proved the ability to remove 71 and 83% of a contaminant of emerging concern, ciprofloxacin (CIP), under ultraviolet (UV) and visible (Vis) radiations, respectively.This study was conducted with financial support from the Portuguese Foundation for Science and Technology (PTDC/CTM-ENE/5387/2014, PTDC/NAN-MAT/28745/2017, UID/FIS/04650/2020, UID/QUI/0686/2020, PTDC/FIS-MAC/28157/2017, SFRH/BD/121780/2016 – B. F. G., 2020.02802.CEECIND – P. M. M.); and the Basque Government Industry Department (ELKARTEK, HAZITEK). This work was carried out in part through the use of the INL Advanced Electron Microscopy, Imaging and Spectroscopy Facility

Interface Engineering in Nanostructured Nickel Phosphide for Efficient and Stable Water Oxidation

An approach to significantly enhance the performance of the cost-effective nickel phosphide catalyst for electrochemical water oxidation has been developed via interfacing with Mg oxide-hydroxide. We have synthesized Ni2P nanoparticles anchored on Mg2O(OH)2-like phase supported on carbon paper. During the oxygen evolution reaction, the well-defined Ni2P nanoparticles serve as precursors for the immediate formation of active and stable nanostructured nickel hydroxide catalyst. As the anode for the oxygen evolution reaction in an alkaline electrolyte, the electrode shows a modest Tafel slope of 48 mV dec–1 and a large turnover frequency of 0.05 s–1 at an overpotential of 0.4 V. Microstructure and composition studies of the catalyst suggest that interfacial strain between Mg- and Ni-containing phases is responsible for high catalytic activity. A significant increase in catalytic activity upon the combination of magnesium compound and transition-metal phosphide suggests an interesting strategy for the controlled and reproducible preparation of active Earth-abundant oxygen-evolving catalysts