A relatively low voltage can be favor of e^- transfer and peroxide generation from dominant 2e^--reduction of O₂ on carbon materials as cathode, with low energy loss. In this study the conversion of As(III) in simulated high arsenic groundwater at low voltage was compared in a mixed and a anode–cathode separated electrolytic system. With applied voltages (the potential difference between cathode and anode) from 0.1 V to 0.8 V, As(III) was found to be efficiently converted to As(V) in the mixed electrolytic cells and in separated anodic cells. The complete oxidation of As(III) to As(V) at 0.1–0.8 V was also achieved on graphite in divided cathodic cells which could be long-running. The As(III) conversion process in mixed electrolytic cells, anodic cells and cathodic cells all conformed to the pseudo first-order kinetics equation. The energy consumed by As(III) conversion was decreased as the applied voltage declined. Low voltage electrolysis is of great significance for saving energy consumption and improving the current efficiency and can be applied to in-situ electrochemical pre-oxidation for As(III) in high arsenic groundwater.

Segmentation of mining-disturbed land is of great significance for eco-geological environment monitoring. Although existing methods possess strong segmentation capabilities, mining-land exhibits irregular edges, different spatial size, and global texture variability, which lead to difficulties in extracting discriminative features, thereby limiting the accuracy performance. This study first built an RGB-based binary semantic segmentation dataset, covering typical mining-lands in Fujian Province of China. Then a spatial prompt and wavelet Mamba-based multi-scale cross-domain feature fusion network (SWDF-Net) was proposed. (1) Wavelet Mamba-based dual-frequency collaborative enhancement module: high-low frequency information was decoupled by wavelet transform, and further collaboratively enhanced by fusion of multiple local details and Mamba-guided global information. It can highlight mining-lands' high-frequency edge features and low-frequency texture patterns. (2) Cross-domain feature alignment and fusion module: cross-domain statistical calibration and channel conditional modulation were used to narrow spatial-frequency feature distribution gap, which facilitates cross-domain feature alignment and effective fusion. (3) Spatial prompt-based multi-scale feature weighted fusion module: pixel-level weight maps were generated by spatial prior prompt that derived from a spatial decoder and edge gate-based branch, which adaptively fuses former multi-scale dual-domain features. The SWDF-Net achieved best Intersection over Union of 72.22% for mining-land and performed competitively on the ISPRS Vaihingen dataset.