A synergistic bioelectrochemical-photocatalytic system for efficient uranium removal and recovery.

Bioelectrochemical system (BES) is a promising technology for uranium recovery, which also enables simultaneous electricity generation. However, the bioelectrochemical recovery of uranium is hindered by its slow process due to the low reduction potential provided by microorganisms. Herein, we developed an innovative bioelectrochemical-photocatalytic system (BEPS) that combines the advantages of BES and photocatalysis, achieving enhanced uranium removal and recovery.

Formation of iron-rich encrustation layer on anammox granules for high load stress resistance: Performance, advantages, and mechanisms.

Anaerobic ammonia oxidation (anammox) is a cost-effective technology but its performance can be seriously inhibited by high load stress. This study has created an innovative iron-rich encrustation layer (IEL) on the surface of anammox granules (AnGS) through the addition of a certain amount of nano zero-valent iron. The IEL was formed through the aggregation of a gel network and the binding of iron species with extracellular polymeric substances (EPS), resulting in a significant increase in settling ability, EPS secretion, and heme content.

Degradation of methylmercury into Hg(0) by the oxidation of iron(II) minerals.

Mercury contamination is a global concern, and the degradation and detoxification of methylmercury have gained significant attention due to its neurotoxicity and biomagnification within the food chain. However, the currently known pathways of abiotic demethylation are limited to light-induced photodegradation process and little is known about light-independent abiotic demethylation of methylmercury. In this study, we reported a novel abiotic pathway for the degradation of methylmercury through the oxidation of both mineral structural iron(II) and surface-adsorbed iron(II) in the absence of light.

Thermodynamic considerations on the combined effect of electron shuttles and iron(III)-bearing clay mineral on Cr(VI) reduction by Shewanella oneidensis MR-1.

Electron shuttles (ESs) and Fe-bearing clay minerals are commonly found in subsurface environments and have shown potential in enhancing the bioreduction of Cr(VI). However, the synergistic effect of ESs at different redox potentials and Fe-bearing clay minerals on Cr(VI) bioreduction, as well as the fundamental principles governing this process, remain unclear. In our study, we investigated the role of ESs and Fe(III) in Cr(VI) bioreduction.

Capacity, stability and energy requirement of divalent mercury uptake by non-methylating/non-demethylating bacteria.

Methylmercury (MeHg) uptake by demethylating bacteria and inorganic divalent mercury [Hg(II)] uptake by methylating bacteria have been extensively investigated because uptake is the initial step of the intracellular Hg transformation. However, MeHg and Hg(II) uptake by non-methylating/non-demethylating bacteria is overlooked, which may play an important role in the biogeochemical cycling of mercury concerning their ubiquitous presence in the environment. Here we report that Shewanella oneidensis MR-1, a model strain of non-methylating/non-demethylating bacteria, can take up and immobilize MeHg and Hg(II) rapidly without intracellular transformation.

Electrocatalytic Removal of Low-Concentration Uranium Using TiO Nanotube Arrays/Ti Mesh Electrodes.

Groundwater containing naturally occurring uranium is a conventional drinking water source in many countries. Removal of low concentrations of uranium complexes in groundwater is a challenging task. Here, we demonstrated that the TiO nanotube arrays/Ti (TNTAs/Ti) mesh electrode could break through the concentration limit and efficiently remove low concentrations of uranium complexes from both simulated and real groundwater.

Spatial distribution, pollution assessment, and source identification of heavy metals in the Yellow River.

The discharge of pollutants into the Yellow River has been strictly controlled since 2013 due to the severe pollution. Thus, the overall water quality of the Yellow River has been becoming better year by year. However, the contamination status and source identification of heavy metals from the entire Yellow River remains unclear.

Oxidation of bioreduced iron-bearing clay mineral triggers arsenic immobilization.

Iron-bearing clay minerals and arsenic commonly coexist in soils and sediments. Redox oscillation from anoxic to oxic conditions can result in structural Fe(II) oxidation in clay minerals. However, the role of structural Fe(II) oxidation in clay minerals on arsenic immobilization is still unclear.

Long-term operational studies of lab-scale pumice-woodchip packed stormwater biofilters.

The performance of three pumice-woodchip packed stormwater biofilter (PWSWBF) systems with three packing volume ratios of pumice to woodchip (1:2, 1:1 and 2:1) were compared. The results show that the PWSWBF system packed with a lower percentage of woodchip attained a higher removal efficiency of TCOD, TN, NH-N and TP, whereas all three systems completely removed nitrate. The highest removal efficiencies for TCOD, TN, NH-N, NO-N and TP were 95%, 70%, 86%, 100% and 100%, respectively.