In this work, a mesoporous carbon material was modified by nitrogen atom by two different ways. The X-ray photoelectron spectroscopy (XPS) results show that the N atoms at the surface mainly exist in pyridine- and pyridone-like forms (around 80 % in atom ratio). The adsorption capacity of phenol and nicotine on mesoporous carbon and two N-containing mesoporous carbons was studied through adsorption isotherms. The adsorption isotherms were interpreted by three models (Freundlich, Langmuir, and Sips equations). Heat-flow microcalorimetry in liquid phase was used to determine the bonding strength between the organic pollutants and the surface of the adsorbents. In addition, the possibility of regeneration of adsorbents was investigated by temperature-programmed desorption (TPD) technique. The obtained values of differential heats and isotherms showed the heterogeneous properties of the mesoporous carbon materials. Comparing the different results obtained from the experiments, the surface area is a key factor for the adsorption of phenol and nicotine in water. The introduction of N improved the adsorption of phenol but did not affect the adsorption of nicotine.

A simple, rapid, sensitive, and inexpensive dispersive liquid–liquid microextraction method was developed for the determination of trace amounts of copper by flame atomic absorption spectrometry (FAAS). N,N′-bis-(2-hydroxy-5-bromobenzyl)-2-hydroxy-1,3-diiminopropane was used as the chelating ligand. Several analytical parameters affecting the microextraction efficiency such as, sample pH, volume of extraction solvent (carbon tetrachloride), concentrations of the chelating ligand and NaCl, and sample volume were investigated and optimized. The effect of the interfering ions on the recovery of copper was also examined. Under the optimum conditions, the detection limit (3σ) was 0.75 μg L⁻¹for copper with a sample volume of 10 mL, and a preconcentration factor of 20 was achieved. The relative standard deviation (R.S.D) for ten independent determinations of a 10 μg L⁻¹solution of Cu(II) was 2.3 %. In order to verify the accuracy of the developed method, different certified reference materials (SLRS-5, QCS-19, Rice flour unpolished high level of Cd NIES 10c) were analyzed and the results obtained were in good agreement with the certified values. The proposed method was applied to tap water, river water, seawater, rice flour, and wheat flour samples. The percentage recovery values for spiked water samples were between 95.4 and 108.4.

The potential for bioremediation of chromium pollution using bacteria was investigated in this study. Five chromium-removing bacteria strains were successfully isolated from Cr(VI)contaminated soils and identified by their 16S rRNA gene sequences. The optimum growth temperature (30–40 °C) and pH (8.5–11) for the five isolates were investigated. The effect of initial Cr(VI) concentrations (0–1,575 mg L⁻¹) on bacterial growth was also studied. Results showed that Pseudochrobactrum saccharolyticum strain W1 had high chromium-removing ability and could grow at Cr(VI) concentrations from 0 to 1,225 mg L⁻¹. To our knowledge, this is the first report of chromium removal by a member of the Pseudochrobactrum genus. Sporosarcina saromensis W5 had the highest chromium-removing rate of 0.79 mg h⁻¹ mg⁻¹biomass. Exopolysaccharide (EPS) production and components of the five bacteria strains were also investigated, and a positive relationship was found between the bacterial chromium removal and EPS production.

The relationship between ambient concentrations of fine particulate matter (PM2.5) and detrimental effects on fauna remains a highly controversial issue. The present study has determined the levels of fine particulate matter and trace metals in the particulate matter as well as in soil and plants in an oil field of Assam in northeastern India in order to assess the effects of oil exploration on muga (Antheraea assama) silk worms. Ambient PM2.5 concentration was monitored daily at two sites during November (one of the driest months) along with the trace metals, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, and Zn. The distance variation of the trace metals was determined by factors related to dispersion and the emission sources. Higher levels of PM2.5 were measured during the night. This might be due to increased emissions from the group gathering station of crude oil done during the night. Significant correlations were observed among the trace metal compositions of the fine particulate matter in ambient air, soil, and plants of the oil field area, and the same were related to the oil exploration activities. Meteorological data and statistical analysis further confirmed the influence of the oil field activities on the levels of PM2.5 and the trace metals.

Groundwater is the principal source of drinking water for at least one third of Earth’s human inhabitants. Thus, protection of groundwater is a critical issue in many locales. Nitrates and other contaminants that impact human health are of particular concern. Mapping of aquifer vulnerability to pollution is a critical first step in implementing groundwater management protection programs; however, mapping is often constrained by generalizations inherent in model formulation and availability of data. In this study, a groundwater vulnerability model, which employs data extracted from widely available national and statewide geospatial datasets, is used to evaluate regional groundwater pollution risk in the Elkhorn River Basin, Nebraska, USA. The model, implemented in a geographic information system (GIS), is specifically structured to address risks of nitrate contamination in agricultural landscapes; thus, land use is a key factor. Modeled groundwater vulnerability was found to be positively correlated with nitrate concentrations obtained from sampled wells. The results suggest that the approach documented here could be used effectively to model regional groundwater pollution risk in other areas.

The extracellular polymeric substance (EPS) extracted from waste-activated sludge after short-time aerobic digestion was investigated to be used as a novel biosorbent for Cd²⁺removal from water. The sorption kinetics was well fit for the pseudo-second-order model, and the maximum sorption capacity of the EPS (430.3 mg Cd²⁺/g EPS) was markedly higher than those of the reported biosorbents. Both Langmuir model and Freundlich model commendably described the sorption isotherm. The Gibbs free energy analysis of the adsorption showed that the sorption process was feasible and spontaneous. According to the results of multiple analytical techniques, the adsorption process took place via both physical and chemical sorption, but the electrostatic interaction between sorption sites with the functional groups and Cd²⁺was the major mechanism.

Elements uptake, histological distributions as well as mycorrhizal and physiological statuses of Atriplex halimus were determined on trace metal and metalloid polluted soils from the surrounding spray zones of a former lead smelter in the South-East coast of Marseille (France). Analyses of heavy metal and arsenic distribution in soil and plant organs showed that A. halimus tolerance is largely due to exclusion mechanisms. No specific heavy metal concentration in leaf or root tissues was observed. However, accumulation of salts (NaCl, KCl, Mg and Ca salts) on leaf bladders and peripheral tissues of roots was observed and may compete with metal element absorption. Occurrence of endomycorrhizal structures was detected in roots and may contribute to lower element transfer from root into the aerial parts of plants. The non-destructive measurements of leaf epidermal chlorophylls, flavonols and phenols showed a healthy state of the A. halimus population on the metal and metalloid polluted sites. Considering the low metal bioaccumulation and translocation factors along with a reduced metal stress diagnosis, A. halimus appeared as a good candidate for phytostabilization of trace metals and metalloids and notably arsenic in contaminated soils of the Mediterranean spray zone. However, its invasive potential has to be determined before an intensive in situ use.

In this study, lead (Pb) and antimony (Sb) sorption experiments were conducted to elucidate the mechanisms of Pb and Sb sorption by combined applications using single or combined applications of hydroxyapatite (HAP) and ferrihydrite (FH), to evaluate the contribution of each material in Pb and Sb sorption, and to assess the chemical stability of the sorbed Pb and Sb. In the combined application, isotherms of Pb sorption and Sb sorption were well fitted to Langmuir and Freundlich isotherm models, respectively. The Pb and Sb amounts sorbed in the combined application were the same levels as the summed totals of those sorbed in the single applications, indicating that in the combined application, Pb sorption and Sb sorption were not suppressed. Pb was mainly sorbed on HAP in the combined application, at a 90 % level of the total adsorbed Pb. The HAP and FH contributions to Sb sorption were 32 and 68 % of the total adsorbed Sb, respectively, and Sb was sorbed on each material independently even in the combined application. The percentages of both Pb and Sb dissolved from the sorbed materials in the combined applications at pH 4 and 6 were the same levels as those in the single applications. However, the percentages of Sb dissolved in both combined and single applications were high at an alkaline pH. These results suggest that HAP and FH in a combined application would be useful for simultaneous Pb and Sb immobilization in soil with acidic to neutral pH, but not in soil with an alkaline pH.

Washing-down parlours and standing areas, following milking on dairy farms, produce dairy soiled water (DSW) that contains variable concentrations of nutrients. Aerobic woodchip filters can remove organic matter, nutrients and suspended solids (SS) in DSW, but the effluent exiting the filters may have to be further treated before it is suitable for re-use for washing yard areas. The performance of a single-layer sand filter (SF) and a stratified SF, loaded at 20 L m⁻² day⁻¹, to polish effluent from a woodchip filter was investigated over 82 days. Average influent unfiltered chemical oxygen demand (CODT), total nitrogen (TN), ammonium–N (NH₄–N), ortho-phosphorus (PO₄–P) and SS concentrations of 1,991 ± 296, 163 ± 40, 42.3 ± 16.9, 27.2 ± 6.9 and 84 ± 30 mg L⁻¹ were recorded. The single-layer SF decreased the influent concentration of CODT, TN, NH₄–N, PO₄–P and SS by 39, 36, 34, 58 and 52 %, respectively. Influent concentrations of CODT, TNT, NH₄–N, PO₄–P and SS were decreased by 56, 57, 41, 74 and 62 % in the stratified SF. The single-layer SF and the stratified SF were capable of reducing the influent concentration of total coliforms by 96 and 95 %, respectively. Although a limited amount of biomass accumulated in the uppermost layers of both SFs, organic and particulate matter deposition within both filters affected rates of nitrification. Both types of SFs produced final water quality in excess of the standards for re-use in the washing of milking parlours.

We present the study of atrazine, the pesticide separation using the typical thin film composite (TFC) membranes, made up of polyamide formation between m-phenylenediamine (MPDA) and trimesoyl chloride (TMC) on the polysulfone membrane matrix. The unreacted acyl moieties in TFC membranes are chiefly responsible for the preferential rejection of bivalent counter ion (SO₄ ⁼) due to their residual charges compared to monovalent (Cl⁻) ion. These two low-pressure-driven membranes show the similar trend as salt and organic markers. Changing the feed matrix is also an interesting direction to improve the performance apart from choosing the membrane. This approach sheds light on the separation behaviour with the addition of biosurfactant. Biosurfactant-mediated filtration showed better performance of the membranes, though it depends on the nature of membranes. The membranes having more porous (in terms of organic markers) structure showed improvement in separation of atrazine. The increase in separation 20.29 % is observed for 200 mg/L biosurfactant for Memb-I, whereas 13.81 % increase is observed for Memb-II.