MIL-53(Al)-graphene oxide (GO) nanocomposites of different GO to MIL-53(Al) mass ratios (1% to 25% GO) were synthesized and tested for removal of arsenite (As(III)), which is a well-known groundwater contaminant. The properties of MIL-53(Al)-GO nanocomposites were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) Spectroscopy, Brunauer-Emmett-Teller (BET) surface area measurements, and Scanning Electron Microscopy (SEM). Batch experiments were performed on MIL-53(Al)-GO nanocomposites for As(III) adsorption in aqueous solutions to investigate adsorption kinetics and isotherm behavior under varying environmental conditions. The effects of solution pH (2 to 11), initial As(III) concentrations (10–110 mg/L), adsorbent dosage (0.2–3.0 g/L), and temperature (298–318 K) on As(III) adsorption were investigated. MIL-53(Al)-GO nanocomposites showed higher adsorption of As(III) than pristine MIL-53(Al) and GO individually. As (III) removal was optimized at a ratio of 3% GO in the MIL-53(Al)-GO nanocomposite, with an adsorption capacity of 65 mg/g. The adsorption kinetics and isotherms followed pseudo-second-order and Langmuir isotherm models, respectively. Overall, these results suggest that MIL-53(Al)-GO nanocomposite holds a significant promise for use in the remediation of As (III) from groundwater and other aqueous solutions.

Selenium pollution has been a topic of extensive research dating back further than the last decade and has attracted significant attention from several environmental and regulatory agencies in order to monitor and control its discharge from myriad industrial sources. The mining industry is a prime contributor of hazardous selenium release in the aquatic systems and is responsible for both acute and chronic impacts on living organisms. Herein we provide an overview of selenium contamination issues, with a specific focus on selenium release from mining industries, including a discussion of various technologies commonly employed to treat selenium-impacted waters from mining discharge. Different cases pertaining to selenium release from Alaskan mines (during years 2000–2015) are also presented, along with measures taken to mitigate high concentration releases. For continued resource exploration and economic development activities, as well as environmental preservation, it is important to fundamentally understand such emerging and pressing issues as selenium contamination and investigate efficient technological approaches to counter these challenges.