Environmental context. Boron, an essential element for human health and the growth of animals and plants, can also be harmful when intake is excessive. Herein, a simple and efficient method for determining boron species in aqueous samples has been developed based on the optical absorption of the pyridoxine or boron–pyridoxine complex. This rapid method is suitable for online analysis, with great significance to drinking water and industrial water treatment.

Environmental context. Vanadium, a metal pollutant from fossil fuels and slags, may be toxic, thereby necessitating an understanding of its environmental chemistry. One important factor that controls the mobility and bioavailability of vanadium is its binding to iron oxides. This study focuses on the characterization and modelling of vanadium adsorption onto ferrihydrite. The new model can be used to simulate the transport and bioavailability of vanadium in the environment.

Environmental context. Wastewater contains various substances such as sulfur-containing chemicals and heavy metals including mercury ions. Several technologies have been developed to trap mercury ions; however, mercury can undergo reactions with sulfite and change to its vapour form, which easily escapes to the atmosphere. Here, we devised a model to predict the formation of vapour-phase mercury as a function of sulfite concentration, temperature and water acidity based on coal-fired power plant wastewater.

Environmental context. Dimethylsulfide is a biogeochemically important sulfur gas emitted from the oceans that can lead to aerosol formation, thereby affecting earth albedo and climate. Studies on the biogeochemistry of dimethylsulfide and its precursors and oxidation products in coastal waters can link the atmospheric chemistry of dimethylsulfide with the bioavailable organic sulfur pool in the oceans. The ensuing information is essential for understanding the biogeochemical dynamics of sulfur and its global cycles.

Environmental context. Dissolved sulfide results in soil acidification and subsequent contaminant leaching via oxidation processes, usually involving manganese oxides. In this work, redox processes were monitored in situ by cyclic voltammetry and HS^– concentrations were semi-quantitatively determined. The method provides qualitative and semi-quantitative assessment for dissolved sulfide and its oxidation intermediates in aqueous systems.

Environmental context. Full mineralisation of synthetic azo dyes in industrial wastewater is a tough job for traditional wastewater treatment technologies. There is an urgent need for the development of both sustainable and environmentally friendly technology capable of fully mineralising these azo compounds. We show that solar-driven advanced oxidation processes are capable of completely mineralising azo compounds with high utilisation of solar energy.