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This work presents a reasonable strategy of optimizing the N : P molar ratio of municipal wastewater to simultaneously restore N‐NH4+ and P‐PO43− via struvite precipitation employing biochar modified with magnesium as the seeding material. The phosphate removal efficiency and ammonium removal efficiency could reach up to 71 % and 100 %, respectively. The remaining phosphate can be restored by other techniques for low phosphate concentration input, such as electrocoagulation. The XRD patterns indicate the appearance of struvite with high nutrient contents including Mg, N and P in the resulting precipitate, suggesting its potential agricultural application. The biochar from rice husk and rice straw modified with MgCl2 solution via a simple procedure could be used as a new seeding material in struvite precipitation to simultaneously restore phosphate and ammonium from wastewater. It has been found that modifying with MgCl2 concentration of 0.5 M and 1 M were enough to improve 14.7 % and 26.5 % of the phosphate removal efficiencies of rice straw‐based and rice husk‐based biochar, respectively. Along with the highly compatible of the post‐precipitated product with soil amendment, the magnesium modified biochars from rice husk and rice straw were highly suitable for enhancing the restoration of phosphate and ammonium via struvite precipitation. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the levels of fluoride in drinking water and its health impact in Semema, Tigray, Ethiopia. Water samples were collected in February, March and April from three potential spring water sources, namely May Atkaru, May Sensela and May Liham. Each sample was analyzed for a variety of physicochemical parameters including fluoride using standard APHA procedures through double beam UV–Visible spectrophotometer, atomic absorption spectrophotometer and titrimetric methods. All the measured physicochemical parameters except hardness (345.78–368.35 mg/L) and alkalinity (231.3–354.6 mg/L) were recorded below the WHO permissible limit set for drinking water. The amount of fluoride in May Atkaru (4.00 mg/L) and May Sensela (3.89 mg/L) was significantly greater than the WHO permissible limit set for drinking water, 1.5 mg/L. Moreover, HQ . 1 from May Atkaru and May Sensela revealed the possibility of dental and skeletal fluorosis over extended exposure to fluoride irrespective of age and sex variations. This confirmed people in the area with mottled teeth are vulnerable to the excessive consumption of fluoride, which poses health risks. Therefore, it needs immediate interventions to minimize the debilitating effect of fluoride in drinking water by creating awareness among the community and policymakers to introduce low-cost defluoridation methods. [ABSTRACT FROM AUTHOR]

In this work, homogeneous, thin-film proton exchange membranes (PEMs) with superior proton conductivities and high methanol rejection were fabricated via a facile synthesis procedure. Sulfonated polyether ether ketone (sPEEK) was crosslinked via a Friedel–Crafts reaction by α,α′-dichloro-p-xylene, a non-hazardous and hydrophobic compound. PEMs with varying crosslinking and sulfonation degrees were fabricated to overcome the traditional trade-off between methanol rejection and proton conductivity. The sulfonation of PEEK at 60 °C for 24 h resulted in a sulfonation degree of 56%. Those highly sulfonated backbones, in combination with a low membrane thickness (ca. 20 µm), resulted in proton conductivities superior to Nafion 117. Furthermore, X-ray photoelectron spectroscopy proved it was possible to control the crosslinking degree via the crosslinking time and temperature. The PEMs with the highest crosslinking degree showed better methanol rejection compared to the commercial benchmark. The introduction of the crosslinker created hydrophobic membrane sections, which reduced the water and methanol uptake. Subsequently, the membrane became denser due to the crosslinking, hindering the solute permeation. Those two effects led to lower methanol crossovers. This study proved the successful fabrication of PEMs overcoming the trade-off between proton conductivity and methanol rejection, following a facile procedure using low-cost and non-hazardous materials. [ABSTRACT FROM AUTHOR]