In this study, a commercial granular activated carbon was modified with sodium hydroxide followed by a cationic surfactant to increase its efficiency for nitrate removal from water. Physicochemical properties of untreated activated carbon and treated activated carbons were characterized in the terms of FTIR spectroscopy, N 2 adsorption-desorption, and SEM analyses. The surface properties of ACs were determined by N 2-adsorption isotherm data and modeled with several mathematical models. The results showed that the combination of two treatments could improve the nitrate removal efficiency, which is mainly attributed to the modification by cationic surfactant, while the porous volume and specific surface area did not seem to play an important role in the nitrate uptake. In batch experiments, the influence of several operating parameters on the nitrate adsorption capacity was investigated including solution pH, adsorbent dosage, contact time, initial nitrate concentration, temperature and competing ions. Small continuous column test was performed to investigate the feasibility of using each adsorbent. Results of this study suggest that using two-step treatment can be a promising method to enhance the efficiency of activated carbon for nitrate removal from water.

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In recent years, silver nanoparticles (AgNPs) are increasingly used in various industries due to their antibacterial properties, which lead to an increase in pollution of the environment and soil ecosystems. However, the ecological effects of soil pollution by AgNPs were poorly studied than that with AgNPs of other metal-based NPs. The aim of this study is to assess the influence of AgNPs on the biological properties of Haplic Chernozem. Silver was introduced into the soil in the form of AgNPs with a concentration of 0.5; 1; 5; 10; 50, and 100 mg/kg in laboratory conditions. The influence of AgNPs on the biological properties of Haplic Chernozem was assessed 30 days after contamination. The degree of reduction in biological properties depends on the AgNPs concentration in the soil. This study showed that the sensitivity to contamination by AgNPs in the total number of bacteria and enzymatic activity was more than that in the abundance of bacteria of the genus Azotobacter. The integrated index of biological state (IIBS) of Haplic Chernozem was decreased by contamination with AgNPs. Silver nanoparticles in the concentration of 10 mg/kg caused a decrease in the indicator by 13% relative to the control. It also decreased IIBS by doses of 50 and 100 mg/kg by 22 and 27% relative to the control. All used biological indicators could be used for biomonitoring, biodiagnosis, bioindication, and regulation of ecological condition of soil contamination by AgNPs.

Lignocellulosic biomass residues can be used as an interesting resource for the production of biochemicals or sustainable fuels. In this optic, lignin represents an interesting raw material for the production of chemicals, such as aromatic compounds, or fuels. This can contribute in moving away from petroleum-based industries to bio-based industries. The aim of this study was to investigate the application of a photocatalytic process using a commercial solution composed by TiO2 doped with AgCl for wheat straw valorization. The study investigated the effect of pH and catalyst concentrations for optimal phenolic compounds production. It was found that the photocatalytic treatment boosted the phenolic production from wheat straw. The efficiency of the process depended on the initial pH and catalyst concentration. Process optimization towards increased phenolic compounds production was performed. Catalyst concentration of 1 g/L and a treatment time of 1.56 hours in alkaline conditions resulted in the highest phenolics production. Use of the photocatalytic treated wheat straw for anaerobic digestion (AD) was also evaluated. Results showed that the AD microbiome is strongly inhibited by the presence of toxic compounds presented in the catalyst-straw solution and specifically, HNO3 was toxic to methanogenic communities. Hence, to succeed in an efficient biorefinery framework where total phenols and biogas production are combined, the usage of HNO3 for catalyst synthesis should be avoided.