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Enhancing soil permeability is of huge practical significance for the in-situ chemical oxidation in soil and groundwater remediation. Hence, we conducted pilot-scale (2 m3 of soil) pneumatic fracturing (PF) and pneumatic fracturing-vacuum extraction (PFV) experiments for improving the fluid infiltration rate in low permeable soil zone in this study. Moreover, the correlation interpretation for soil permeability enhancement suffers from limited databases and complexities (i.e., geological properties) due to many factors that affect the fluid injection performance toward low permeability soil. Further, this is the first paper to introduce a novel approach using a soft computational model, a feedforward backpropagation artificial neural network (FFBP-ANN), to predict the infiltration coefficient for PF or PFV treated soils. As a result, the PV and PFV methods significantly enhanced the infiltration coefficients. Notably, the established FFBP-ANN model with the configuration of eight neurons associated with one hidden layer connected by tangent sigmoid transfer function and trained by Levenberg-Marquart backpropagation algorithm achieved the 0.999 of regression with 0.001 of mean square error accuracy performance. Therefore, this study shows that PFV can significantly enhance the infiltration coefficient, and the computational FFBP-ANN models can help extend the infiltration coefficient estimation for low permeable soil. [Display omitted] • Infiltration coefficients for low permeable soil were significantly enhanced by the PFV. • FFBP-ANN models for infiltration coefficient prediction have been established. • The developed model exhibited prediction accuracy with MSE (0.001) and R2 (0.999). [ABSTRACT FROM AUTHOR]

Thermal plasma blasting technology has been widely applied for rock cracking. Though, the application for environmental remediation has yet to be reported. Since the delivery of remediation agents into diesel contaminated clayey zones are exceptionally challenging, herein, this study explores the effect of pilot-scale thermal plasma blasting for soil fracturing and concurrently dispersing the Fenton reagent into the diesel contaminated silty soils. Six times plasma blasting with sole H 2 O 2 at 20 kV had the highest degradation of diesel (>97%) with an equilibrium time of 3 h, and the final diesel concentration was below the South Korean regulated health standard (500 mg kg−1). This study highlights plasma blasting able to deliver H 2 O 2 instantaneously and homogeneously into contaminated zone while promoting Fenton reaction synergism (f syn : 2.04) between H 2 O 2 and ≡Fe surface for effective remediation. Furthermore, the remediation cost (USD 4 metric ton−1) is much lower than most reported in situ technologies. [Display omitted] • First time applying plasma blasting in soil treatment application. • Plasma blasting assist delivery of Fenton reagent into clayey soil. • Solely ≡Fe2+ minerals are sufficient to active Fenton reaction. • Synergistic effect between plasma and Fenton reaction. • Comparatively lower cost (USD30) than conventional treatment. [ABSTRACT FROM AUTHOR]

Atmospheric non-thermal dielectric barrier discharge (DBD) plasma has gained considerable attention due to its cost-efficiency, environmental friendliness, and simplicity. However, certain deficiencies restrict its broad application. Herein, the DBD plasma was used to disrupt three model pharmaceutically active compounds (PhACs), sulfamethoxazole (SMX), ibuprofen (IBP), and norfloxacin (NFX), by varying parameters, such as gas type (Ar, N 2 , O 2 , and air) and flow rate (1–4 L min−1). The air plasma discharge had the highest degradation efficiency, and the air flow rate was optimized at 2 L min−1. However, only 10% of IBP was removed by the sole plasma, whereas NFX and SMX were entirely removed after 30 min. Since the air plasma discharge generates reactive oxygen and nitrogen species in a chained reaction, the remaining NO 2 − and NO 3 − in the aqueous phase were problematic. Therefore, by coupling plasma with electrolysis using Cu/reduced Cu nanowire (R-CuNw) as the anode/cathode, all three PhACs were removed within 30 min, and NO 2 − and NO 3 − were completely reduced to NH 3 with cathodic reduction. Moreover, the electrical energy per order (E EO, 0.04 kWh L−1) and treatment cost (0.003 USD L−1) were much lower than those of the single system. This system demonstrates great potential for water remediation, and the production of NH 3 as a value-added by-product remarkably improves its practicality and is of great importance in agriculture and energy-related industries. [Display omitted] • DBD plasma was insufficient to remove a wide spectrum of PhACs. • Plasma air discharge with 2 L min−1 had the optimal degradation efficiency. • Synergism in E-plasma increased ROS concentration and O 3 solubility. • E-plasma simultaneously removed PhACs and produced NH 3 from NO 3 − • Energy efficiency and treatment cost significantly reduced with E-plasma. [ABSTRACT FROM AUTHOR]

• Mg-Fe-LDH embedded with PAM/PVA for As(III)/As(V) removal was studied for the first time. • PAM 40 /PVA 30 -LDH has higher stability in aqueous phase compared to Mg-Fe-LDH • PAM/PVA delaminated the Mg-Fe-LDH structures and enhances As(III)/As(V) sorption. • Hydrogen bonding, ion exchange of SO 4 2− and complexation are the dominant mechanism for As(III)/As(V) removal. Controlling the particle size and aggregation of nanosheet layers in layered double hydroxides (LDHs) is critical for their application. Herein, we report the preparation of Mg-Fe LDH through a co-precipitation method. The LDH was embedded using polyacrylamide (PAM) and polyvinyl alcohol (PVA; the LDH was designated as PAM/PVA-LDH) for As(III) and As(V) removal. We found that doping with 0.3 mL PVA (2 g L-1) and 0.4 mL (20 g L-1) PAM solution delaminated the nanosheet layers of 1 g of the LDH (PAM 40 /PVA 30 -LDH) and restructured the crystal phase from monoclinic to orthorhombic. This increased the surface area and pore volume. Furthermore, PAM 40 /PVA 30 -LDH exhibited higher affinity for As(III) and As(V) removal with maximum adsorption capacities of 14.1 and 22.8 mg g−1, respectively, compared to LDH alone with adsorption capacities of 7.1 and 7.9 mg g−1, respectively. It was found that the highest adsorption capacities of As(III) and As(V) using PAM 40 /PVA 30 -LDH occurred at pH ∼7 and pH 2.5, respectively. X-ray photoelectron spectroscopy analysis revealed that the removal of As(III) and As(V) on PAM 40 /PVA 30 -LDH was mainly attributable to ion exchange with intercalated SO 4 2-, hydrogen bonding, and complexation mechanisms. These findings illustrate that PAM 40 /PVA 30 -LDH would be an excellent adsorbent for the remediation of arsenic-polluted wastewater. [ABSTRACT FROM AUTHOR]

In this study, palm shell activated carbon powder (PSAC) and magnesium silicate (MgSiO 3) modified PSAC (MPSAC) were thoroughly investigated for fluoride (F−) adsorption. F− adsorption isotherms showed that PSAC and MPSAC over-performed some other reported F− adsorbents with adsorption capacities of 116 mg g−1 and 150 mg g−1, respectively. Interestingly, the MgSiO 3 impregnated layer changed the adsorption behavior of F− from monolayer to heterogeneous multilayer based on the Langmuir and Freundlich isotherm models verified by chi-square test (X2). Thermodynamic parameters indicated that the F− adsorption on PSAC and MPSAC was spontaneous and exothermic. PSAC and MPSAC were characterized using FESEM-EDX, XRD, FTIR and XPS to investigate the F− adsorption mechanism. Based on the regeneration tests using NaOH (0.01 M), PSAC exhibited poor regeneration (<20%) while MPSAC had steady adsorption efficiencies (∼70%) even after 5 regeneration cycles. This is due to highly polarized C–F bond was found on PSAC while Mg–F bond was distinguished on MPSAC, evidently denoting that the F− adsorption is mainly resulted from the exchange of hydroxyl (-OH) group. It was concluded that PSAC would be a potential adsorbent for in-situ F− groundwater remediation due to its capability to retain F− without leaching out in a wide range pH. MPSAC would be an alternative adsorbent for ex-situ F− water remediation because it can easily regenerate with NaOH solution. With the excellent F− adsorption properties, both PSAC and MPSAC offer as promising adsorbents for F− remediation in the aqueous phase. • MgSiO 3 impregnated on PSAC for fluoride removal was studied for the first time. • MPSAC showed higher fluoride adsorption capacities compared to PSAC. • Anions inhibited F− adsorption with the following sequence: Cl− < NO 3 − < SO 4 2-. • PSAC had stable sequestration capacities of fluoride due to strong C–F bond formation. • MPSAC had high regeneration capacities for ex-situ fluoride treatment using NaOH. [ABSTRACT FROM AUTHOR]