The removal efficiencies of four different parabens (methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP)) using Fenton reagent, UV irradiation, UV/H₂O₂, and UV/H₂O₂/Fe²⁺ were evaluated to assess the level of paraben degradation achieved using different advanced oxidation processes (AOPs). UV irradiation by itself provided paraben conversions between 27 and 38 % after a reaction time of 180 min. The UV/H₂O₂ system increased the paraben conversion to values between 62 and 92 %, and the Fenton process was revealed as inefficient in paraben degradation within the experimental conditions used. Photo-Fenton presented similar removal rates to the UV/H₂O₂ process. Among the four parabens studied, butylparaben was the most easily removed, and it was possible to attain degradations higher than 90 %. In the UV/H₂O₂ and photo-Fenton processes, the overall kinetic constant could be split into two main components: direct oxidation by UV radiation (photolysis) and oxidation by free radicals (mainly HO•) generated from the photodecomposition of H₂O₂. This work reveals that UV-driven oxidation processes can be widely used to remove parabens from contaminated aqueous solutions.

This study investigates the removal of Cu(II) from aqueous solutions by biosorption-flotation as a function of several parameters, such as collector type, pH, molar ratio, air pressure, time, and initial metal concentration. Dissolved air flotation was applied as a polishing technique for the additional purification of the effluent resulted after biosorption. The obtained results were supported by the physicochemical characteristics of the surfactants used as flotation reagents and suggested that cetylpyridinium bromide (CPB) was the optimum collector for Cu(II) ion removal. Cu(II) removal efficiency exhibited a maximum of 97.09 % in the following operating conditions: biosorption pH 4.5, Cu(II) initial concentration 250 mg/L, biosorbent dosage 0.5 % w/v, agitation rate 200 rpm, temperature 20 °C, biosorption time 30 min, flotation pH 9, air pressure 4.5 × 10⁵ Pa, dilution ratio 3:1, flotation time 10 min, collector CPB 0.01 M, and molar ratio collector/Cu(II) 5 × 10⁻¹:1. The experimental data confirmed that the flotation stage contributed to the optimization of the overall separation process.

A 1D reactive model is developed to simulate the EDTA chelating process in a lead (Pb)-contaminated saturated soil. The model is implemented using a multistep numerical approach in order to avoid numerical diffusion assuring at the same time the algorithm stability. The model takes into account first-order reactions where the lead species are splitted into three fractions: C₁(easily mobilized lead), C₂(lead associated with iron and manganese oxides), and C₃(lead bound to organic matter and in the residual fraction). Two different mobilization kinetics (“slow” and “fast”) are considered for each fraction. The model was therefore calibrated and validated using laboratory experimental data. A sequential extraction procedure was conducted to evaluate the lead mobilization due to the EDTA flushing through the column and to take into account the different soil fraction at which the metal is bound. Several remediation scenarios are used to show the suitability of the model to provide information and knowledge of the best EDTA feed and flux conditions for the lead extraction from soil. The model can therefore be considered as a tool to know in advance the performances of a remediation treatment and to optimize the extraction process minimizing the chelating agent costs and its effects on the soil.

Nikola Tesla B power plant (TENT-B), located on the Sava River in Obrenovac, 52 km west from the Serbian’s capital, Belgrade, is the second largest coal-fired power plant in the country, consisting of two blocks of 620 MW each. Samples of fresh coal ash obtained by coal combustion in TENT-B, as well as coal ash samples from the surface and 1-m depth of active, currently filled, and passive, previously filled and not currently used, cassettes, were taken from the coal ash dump. Ultrasonic extracts of the samples were analyzed using gas chromatography with mass selective detection (GC/MSD) in order to identify and quantify 16 priority polycyclic aromatic hydrocarbons (PAHs). Two PAH extraction mechanisms during coal ash dumping and storage processes are discussed and significant differences between them were established. PAH concentrations in the ash samples were compared statistically. Correlations between samples and sampling points were established, and leaching potential of samples was examined. Concentrations of PAHs can be reduced in coal ash sediments by environmental influences only after long time periods, and PAHs with two six-membered rings pose danger to underground waters, while PAHs with three rings pose danger to soil sediments.

The feasibility of batch and continuous (60, 80, and 100 mL/min) mode photocatalysis systems in real-time livestock wastewater treatment was investigated. The photocatalytic experiments were conducted with two types of photocatalysts namely slurry titanium-dioxide (UV-TiO₂) and granular activated carbon supported TiO₂(GAC-TiO₂). The performance of the systems was compared using economic analysis based on cost and time required to attain maximum efficiency. The photocatalytic reactors operated with GAC-TiO₂was highly effective under both batch (total volatile solids (TVS) removal of 100 % within 6 min and a total operational cost of 0.68 USD per kg of TVS removal) and continuous (at 60 mL/min) (TVS removal of 63 % at a hydraulic retention time (HRT) of 240 min and a total operational cost of 62.16 USD per kg of TVS removal) mode experiments. The economic analyses indicated that cost reduction was a function of optimum time taken for maximum removal efficiency. Subsequently, the experiments were repeated with ultraviolet light (UV) alone, UV-GAC, and GAC alone to quantify effects of adsorption and photolysis. The results confirmed that the effect of GAC in the treatment/degradation of livestock wastewater by adsorption was negligible. However, the presence of GAC in UV systems propelled the rate of biochemical oxygen demand (BOD) and TVS removals. The entire observations reveal that the degradation was mainly by two reaction mechanisms: firstly, adsorption on the GAC surface and secondly by photocatalytic degradation on the GAC-TiO₂surface. Therefore, GAC-TiO₂photocatalysis could be cost-effectively applied for high-rate treatment of industrial wastewaters.

Mesostructured CuMnCeO ₓ catalysts were prepared and tested in chlorobenzene destruction. Mn and Cu phases enter CeO₂matrix with a fluorite-like structure to form Cu–Mn–O–Ce solid solution. Both synthesis protocol and metal-doping content affect the metal state, reducibility, and oxygen distribution of composites. The c₀.₁₅c₀.₁₅c₀.₇sample exhibits the highest activity with 90 % of chlorobenzene oxidized at around 250 °C. Enhanced oxygen concentration and mobility, and abundant oxygen vacancy promote the desorption of adsorbed Cl, which guarantees the superior stability of CuMnCeO ₓ . Incorporation of CuO and MnO ₓ effectively inhibits the formation of organic byproducts, such as phenolates, maleates, and o-benzoquinone, especially at elevated temperatures.

As a biopolymer-modified building block, a poly-dopamine layer can be utilized with a wide range of inorganic and organic materials for an adsorptive and microbial remediation. In this study, dopamine (DOPA) was used as a structural platform to bind silver onto the surface of kapok fibers, and a composite of surface-modified kapok fibers coated with DOPA along with silver were successfully manufactured. After a silver-coating process, a very strong antibacterial property was exhibited against Staphylococcus aureus with a high antibacterial efficiency, over 99 %, which could last for 48 h in peptone water. Enumeration determination was carried out in a spread plate method. For a comparative study, the antibacterial activity of raw kapok fibers and chemically enhanced kapok fibers with DOPA and silver was also evaluated. The results indicated that the chemically enhanced kapok fibers were very useful in controlling a microbial activity on a surface environment.

The aim of the present work was to determine the effect of the simultaneous adsorption of lead(II)-cadmium(II), lead(II)-phenol, and cadmium(II)-phenol by activated carbon cloths (ACCs). Three commercial ACCs were characterized and tested for individual metal adsorption, and competitive adsorption experiments were carried out with the best ACC (AW1104). The specific surface areas of all ACCs were >1000 m²/g, yet only AW1104 presented a high content of acidic sites (1.0 meq/g). Competitive adsorption experiments indicate that cadmium uptake is strongly affected by the presence of lead. This can be attributed either to a more favorable hydroxyl complexation of Pb(II) (that adsorbs strongly),or to the smallest hydrated radius of the Pb(II) molecule (that more easily diffuses). On the contrary, lead uptake was not considerably decreased in the presence of an equimolar cadmium concentration, indicating that AW1104 is more selective for Pb(II) than for Cd(II). Also, the presence of phenol causes a decrease in the heavy metal adsorption capacity, especially for cadmium (40 %). The former might be due to adsorbed phenol, which creates steric hindrance for cations to adsorb on specific oxygenated groups on the ACC. On the other hand, when heavy metals adsorb on the ACC surface, they stabilize the repulsive forces on the surface of the ACC for phenol adsorption, resulting in an increase of the adsorption capacity.

Mosses and lichens are widely used to detect changes in the environmental concentrations of potential contaminants. Several studies have shown the usefulness of transplanted mosses and/or lichens to monitor air depositions of inorganic and organic pollutants at different scales. Here, we present the results of a biomonitoring study carried out in two cities, London (United Kingdom) and Naples (Italy), using four biomonitors (two lichens and two mosses). The lichens, Pseudevernia furfuracea (L.) Zopf var. furfuracea and Parmelia sulcata Taylor, and mosses, Sphagnum capillifolium (Ehrh.) Hedw. and Hypnum cupressiforme Hedw., were exposed in bags in urban streets of Naples and London and in semi-rural and rural areas. Samples were analysed for Cd, Cr, Cu, Fe, Ni, Pb, V and Zn by atomic absorption spectrometry after acid digestion and for 16 EPA polycyclic aromatic hydrocarbons (PAHs) by gas chromatography coupled to mass spectrometry after matrix solid-phase dispersion. For heavy metals, the comparison between the selected mosses indicated that, in all exposure sites, S. capillifolium had a better accumulation performance than H. cupressiforme, whereas for the lichens, it was P. furfuracea which accumulated higher concentrations of metals. Also for total PAHs, S. capillifolium showed a good accumulation capability compared to the other biomonitors investigated, especially compared to H. cupressiforme. It was observed an increasing heavy metal and PAH uptake by biomonitors from rural to urban sites, in both cities.

A novel and eco-friendly xanthan gum-g-poly(acrylic acid)/laterite (XG-g-PAA/laterite) organic-inorganic composite polymer used as chemical sand-fixing agent (CSFA) was successfully prepared by grafted copolymerization of natural XG, partially neutralized acrylic acid (NaA), and laterite in solution. FTIR spectra confirmed that NaA had been grafted onto XG chains, and the –OH groups of laterite participated in polymerization reaction. The influence of the content of CSFA on sand-fixing effect was investigated, and the results of the aging test indicated that the CSFA had remarkable water resistance, heat resistance, anti-freeze-thaw, and anti-ultraviolet aging performances, which could meet the requirement of application in the harsh desert environment. Moreover, it also showed excellent water-retaining and anti-evaporation properties.