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When fluoride levels in water exceed permitted limits (>1.5 mg L−1), water pollution becomes a major concern to humans.

Capacitive deionization (CDI) is a newly developed desalination technology with low energy consumption and environmental friendliness. The surface area restricts the desalination capacities of traditional carbon-based CDI electrodes while battery materials emerge as CDI electrodes with high performances due to the larger electrochemical capacities, but suffer limited production of materials. LiMn

Capacitive deionization (CDI) is an emerging eco-friendly desalination technology with mild operation conditions. However, the energy consumption of CDI has not yet been comprehensively summarized, which is closely related to the economic cost. Hence, this study aims to review the energy consumption performances and mechanisms in the literature of CDI, and to reveal a future direction for optimizing the consumed energy. The energy consumption of CDI could be influenced by a variety of internal and external factors. Ion-exchange membrane incorporation, flow-by configuration, constant current charging mode, lower electric field intensity and flowrate, electrode material with a semi-selective surface or high wettability, and redox electrolyte are the preferred elements for low energy consumption. In addition, the consumed energy in CDI could be reduced to be even lower by energy regeneration. By combining the favorable factors, the optimization of energy consumption (down to 0.0089 Wh·gNaCl−1) could be achieved. As redox flow desalination has the benefits of a high energy efficiency and long lifespan (~20,000 cycles), together with the incorporation of energy recovery (over 80%), a robust future tendency of energy-efficient CDI desalination is expected.

Bauxite is a widely available Al-O-rich mineral with great potential for abating fluoride. However, low adsorption capacity, a narrow workable pH range, and a lack of clarity on the best removal mechanism hinder its application. In this work, a highly efficient bauxite nanocomposite (Bx-Ce-La@500) was synthesized via doping and pyrolysis, and its fluoride adsorption in industrial wastewater was examined. Doping Ce/La synergistically improved the fluoride adsorption affinity of the composite (from pH

Capacitive deionization (CDI) is a newly developed desalination technology with low energy consumption and environmental friendliness. The surface area restricts the desalination capacities of traditional carbon-based CDI electrodes while battery materials emerge as CDI electrodes with high performances due to the larger electrochemical capacities, but suffer limited production of materials. LiMn2O4 is a massively-produced lithium-ion battery material with a stable spinel structure and a high theoretical specific capacity of 148 mAh·g−1, revealing a promising candidate for CDI electrode. Herein, we employed spinel LiMn2O4 as the cathode and activated carbon as the anode in the CDI cell with an anion exchange membrane to limit the movement of cations, thus, the lithium ions released from LiMn2O4 would attract the chloride ions and trigger the desalination process of the other side of the membrane. An ultrahigh deionization capacity of 159.49 mg·g−1 was obtained at 1.0 V with an initial salinity of 20 mM. The desalination capacity of the CDI cell at 1.0 V with 10 mM initial NaCl concentration was 91.04 mg·g−1, higher than that of the system with only carbon electrodes with and without the ion exchange membrane (39.88 mg·g−1 and 7.84 mg·g−1, respectively). In addition, the desalination results and mechanisms were further verified with the simulation of COMSOL Multiphysics.

Farming is the major economic activity of the people in the Asutifi-North District of Ghana however, farmers in this District are mainly characterized by small-farm holdings of less than 3 acres per farmer as a result of shrinking agricultural land due to increasing small and large-scale mining in the District. Currently, mining has become the major competitor to farming in terms of land-use conversion within the District. Though mining activities have led to several land-use conversions, little or no studies have been done in that regard. Studies over the years have focused on the environmental impacts of mining with less emphasis on the impacts of mining on farmers' welfare. This paper examines the factors influencing farmers' participation in land-use conversion for mining, its impacts on farmers' welfare, and the criteria of compensation given to affected farmers by the large-scale mine. Multi-staged sampling comprising both purposive and random sampling techniques was employed to gather data from 300 farmers in 5 mining communities in the district. The data obtained were analyzed using descriptive statistics and the Heckman two-stage model involving the Probit and OLS equations. Results indicate that variables such as farmer's age, sex, distance from household to farm, farmer's experience, total land size, and distance to the nearest access road were factors that influenced farmers' decision to participate in land-use conversion. Also, participants of land-use conversion had an annual income of (GH₵ 189)-$31.68 more than the non-participants however, their incomes are not sustainable hence compelling them into illegal mining. This paper has a guiding significance for policy decision making for gold mining in Ghana.