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Abstract: This work demonstrates the combination of UV/persulfate and adsorption processes for treating 2,2,3,3-tetrafluoro-1-propanol (TFP) wastewater. Under the optimum conditions, 20mM persulfate , 254nm UV–C, and pH 3, 99.7% of TOC removal from an initial TFP solution of 1.39mM was achieved. The photolysis of persulfate by UV irradiation yielded the sulfate radical with high activity, which mineralized most of the TFP in 2h. The released fluoride ions were then removed by using a waste iron oxide, BT-4 adsorbent. 20gL−1 BT-4 adsorbed 95% of the fluoride that was produced by mineralization of 1.39mM TFP. The kinetics and isotherms of adsorption were examined to determine the fluoride removal efficiency of BT-4 which co-existed with the sulfate ions from the consumed sulfate radicals. Accordingly, the kinetics of adsorption was described by a pseudo-second-order rate model, while the adsorption isotherms were well fitted with the Langmuir model. BT-4 had a high adsorption capacity of 26.4mgg−1 (25°C) in removing the fluoride from TFP mineralization, suggesting that the co-existing sulfate ions never significantly affected the fluoride removal efficiency. [Copyright &y& Elsevier]

Activated carbon (AC), prepared from dried loofah sponge, was supported on nickel foam to fabricate AC/Ni electrodes. The characteristics of ammonium electrosorption on AC/Ni electrodes was studied. Results showed that AC prepared in one-step activation (without pre-pyrolysis), i.e., OAC, had relatively low crystallinity, high mesoporosity, and high specific capacitance compared to those made in two-step carbonation followed by activation. Adsorption and desorption density of NH 4 + were measured at constant potential of −1.0 V (vs. Hg/HgO) and +0.1 V (vs. Hg/HgO), respectively. Non-faradaic charging contributed to the electrochemical storage and adsorption of ammonium ions on the AC surface with a maximal charge efficiency of 80%, at an applied potential of −1.0 V (vs. Hg/HgO). Multiple-layer adsorption isotherm better described the electrosorption of ammonium ion on OAC/Ni electrodes yielding a maximum adsorption capacity of 6 mg-N g−1, which was comparable with other similar systems. Overall, results clearly demonstrated the effect of synthesis strategy on the capacitive charging behaviors of AC/Ni electrodes and its relationship to NH 4 + electrosorption. Image 1 • Dried loofah sponge was used to prepare activated carbon successfully. • One step activation without pre-pyrolysis yielded activated carbon of high specific capacity. • Activated carbon-nickel foam (OAC/Ni) electrode exhibited 80% charge efficiency. • OAC/Ni electrodes yielded a maximum ammonium adsorption capacity of 6 mg-N g−1. [ABSTRACT FROM AUTHOR]