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Abstract Sodium ion hybrid capacitors (SIHC) are emerging as promising next‐generation energy storage devices with high energy/power density. Presodiation is an essential part of SIHC production due to the lack of sodium sources in the cathode and anode. However, in the current presodiation methods, electrochemical presodiation by galvanostatic current charging and discharging requires a temporary half‐cell or a complex reassembling process, which severely hinders the commercialization of SIHC. Herein, in situ synthesized Na2S infiltrated in activated carbon was used as a sodium salt additive for supplying Na+ in SIHC. Due to a low ratio of Na2S additive attributed to high theoretical specific capacity, the fabricated Na2S/activated carbon composite//HC SIHC can show a higher energy density of 129.71 Wh kg−1 than previously reported SIHC on presodiation of cathode additives. Moreover, the designed SIHC shows an excellent cycling performance of 10,000 cycles, which is attributed to the Na2S additive with the advantages of low decomposition potential and no gas generation. This work provides a novel approach for the fabrication of highly efficient Na2S additive composite cathodes for SIHC.

The demand for nickel, cobalt, and manganese is increasing owing to their critical role in the performance of lithium-ion batteries. Precipitation is simpler to operate than solvent extraction in the separation of metal ions. In this work, precipitation-based procedures were developed to separate Co(II), Mn(II) and Ni(II) from synthetic chloride solutions. Dimethylglyoxime (DMG) was effective in selectively precipitating Ni(II) from the chloride solutions containing Co(II) and Mn(II). Solution pH greatly affected the precipitation of Ni(II) by DMG. In the first procedure, Ni(II) was first precipitated using DMG from solution with initial pH 6 at a DMG/Ni(II) molar ratio of 3, a reaction time of 30 min and then Co(II) was separated from the filtrate by precipitation with Na2S, with optimal conditions being an initial pH of 6, a Na2S/Co(II) molar ratio of 2 and a reaction time of 15 min. In the second procedure, both Ni(II) and Co(II) was simultaneously precipitated with Na2S, leaving Mn(II) in the filtrate. Then the mixed sulfides of Co(II) and Ni(II) were dissolved by using HCl solution containing NaClO as an oxidizing agent. From the leaching solution, Ni(II) was separated by precipitation with DMG. Optimum conditions for the separation conditions were obtained. In both procedures, the separation degree among the three metal ions was higher than 99%. The developed procedures were simple and effective for the separation of the three metal ions compared to solvent extraction. [ABSTRACT FROM AUTHOR]

Sodium ion hybrid capacitors (SIHC) are emerging as promising next‐generation energy storage devices with high energy/power density. Presodiation is an essential part of SIHC production due to the lack of sodium sources in the cathode and anode. However, in the current presodiation methods, electrochemical presodiation by galvanostatic current charging and discharging requires a temporary half‐cell or a complex reassembling process, which severely hinders the commercialization of SIHC. Herein, in situ synthesized Na2S infiltrated in activated carbon was used as a sodium salt additive for supplying Na+ in SIHC. Due to a low ratio of Na2S additive attributed to high theoretical specific capacity, the fabricated Na2S/activated carbon composite//HC SIHC can show a higher energy density of 129.71 Wh kg−1 than previously reported SIHC on presodiation of cathode additives. Moreover, the designed SIHC shows an excellent cycling performance of 10,000 cycles, which is attributed to the Na2S additive with the advantages of low decomposition potential and no gas generation. This work provides a novel approach for the fabrication of highly efficient Na2S additive composite cathodes for SIHC. [ABSTRACT FROM AUTHOR]

The presented scientific research reveals the results of experiments on the precipitation of arsenic in the form of sulfide (As2S3) from the Daridag thermal water using sodium sulfide as a reagent. The main factors impacting the precipitation of the As2S3 compound were determined: the amount of precipitant (Na2S), the ratio of solid and liquid phases (S:L), pH of the initial solution, precipitation time and temperature, also optimal parameters were obtained. According to the results obtained, the yield during precipitation of arsenic tri-sulfide from from thermal water under certain temperature conditions (t=30-450°, pH=1-2; S:L - 1:1000; t = 30-50 min.) were 99.6 %. The properties of the samples were studied by physicochemical research methods (X-Ray, SEM/EDS). X-ray phase analysis showed that the sediment sample obtained under these conditions is X-ray amorphous. The composition and morphology of the obtained sample was confirmed by scanning electron microscopy and spectroscopy (SEM/EDS). [ABSTRACT FROM AUTHOR]

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At the Sarcheshmeh Copper Complex, copper and molybdenum minerals float cumulatively. In this step, copper minerals are floated using sulfhydryl collectors and molybdenum mineral is floated with a collector such as Gasoline; Then, in the molybdenum processing plant, copper minerals are depressed using sodium sulfide, and the molybdenite is floated. One of the factors affecting in depress of minerals containing copper and iron is pH. In this study, the appropriate pH value and the best place to add the pH reducing agent were determined to increase the efficiency of the molybdenum flotation circuit. For this purpose, and according to the places where it is possible to add acid operation, the circuit was divided into three parts: rougher stage, third and fifth cleaning stage, and samples were collected from these parts. The results showed that by decreasing the pH in the fifth cleaning stage from 12 to 10.5, copper and iron recovery decreases and efficiency increases. Therefore, the best place to add sulfuric acid, is the fifth cleaning stage. [ABSTRACT FROM AUTHOR]

Despite the potential of sodium sulfide (Na 2 S) for phosphorus (P) recovery from iron-phosphate waste, the underlying mechanism regarding its impact on P conversion and product quality has not been well addressed. In this study, the effects of Na 2 S addition on P release and recovery from a chemical-enhanced phosphorus removal (CEPR) sludge during anaerobic fermentation were systematically investigated. The results revealed that the effective mobilization of P bound to Fe (Fe–P) by Na 2 S dominated the massive P release from the CEPR sludge, while the organic P (OP) release was not significantly enhanced during anaerobic fermentation. Due to the rapid reaction of Na 2 S with Fe–P and the prevention of Fe(II)–P precipitation by excess S2−, the Fe–P was decreased by 9.7%, 15.2% and 24.9% at S:Fe molar ratios of 0.3, 0.5 and 1, respectively. After anaerobic fermentation, the released P mainly existed as soluble phosphate (SP), P bound to Ca (Ca–P) and P bound to Al (Al–P). The nitrogen and P contents in the fermentation supernatant significantly increased with higher S:Fe ratios, facilitating the efficient recovery of P as high-purity struvite. However, the increased Na 2 S dosage deteriorated the sludge dewaterability because of the dissolution of hydrophilic extracellular polymeric substances and the looser secondary structure of proteins. Comprehensively considering the P recovery, sludge dewaterability and economic cost, the optimal Na 2 S dosage was determined at the S:Fe ratio of 0.3. These findings provide novel insights into the role of Na 2 S in P recovery as struvite from CEPR sludge. [Display omitted] • Effective mobilization of Fe–P by Na 2 S dominated the release of P from CEPR sludge. • Released P was mainly present in soluble phosphate, Ca–P and Al–P. • Dissolution of hydrophilic EPS deteriorated sludge dewaterability. • Struvite with a purity of 67% was recovered from the sludge fermentation supernatant. • The optimal Na 2 S dosage was determined for P release with better dewaterability. [ABSTRACT FROM AUTHOR]