The synthesis, characterization, and photocatalytic evaluation of titania-loaded MCM-41 with and without Au doping are reported in the present study. The samples were characterized by powder XRD, TEM, low temperature N₂adsorption/desorption, UV–Vis, and FTIR. UV-induced vapor-phase photo-oxidation of acetone was used as a probe reaction to study the role of Au in mineralization of volatile organic compounds (VOCs), viz. acetone at different concentrations. The doping of Au in titania-loaded MCM-41 resulted in the decrease of BET surface area, total pore volume, and average pore size. UV–Vis diffuse reflectance spectra of Au-doped titania-loaded MCM-41 showed the red shift in their absorption bands compared to titania-loaded MCM-41. The activity of mineralization of acetone by photocatalysis for 2 % Au-doped titania-loaded MCM-41 was found to be ∼1.6 times higher than titania-loaded MCM-41. The presence of cocatalytic nanosized gold might be responsible for their enhanced activity on account of the delayed recombination of electron/hole pair. Although, almost complete mineralization of acetone was observed irrespective of the initial concentration of acetone in air (up to 3.72 mol%) by all the catalysts, 2 wt.% Au-doped titania-loaded MCM-41 has shown the most enhanced activity.

Graphene oxide (GO) nanosheets were used as adsorbent material for the removal of clofibric acid (CA) which was difficult to be removed from wastewater by traditional wastewater treatment technique. Adsorption kinetics, adsorption equilibrium, and effect of pH, ionic strength, and humic acid (HA) of the adsorption of CA onto the GO nanosheets in aqueous solution were investigated in detail. Adsorption isotherm studies indicated that the Langmuir isotherm equation fitted the sorption isotherm data better than Freundlich model and the maximum adsorption capacity of GO nanosheets for CA was 994 mg g⁻¹. In addition, adsorption kinetics data showed that the sorption of CA on GO nanosheets reached equilibration within a few minutes and were well fitted by pseudo second-order model. The results of the effects of environment factors indicated that CA sorption on GO nanosheets was weakly affected by ionic strength and strongly depended on pH and HA because of the structure of CA and the large number of oxygen-containing function groups presented on the surface of GO nanosheets. Besides, the removal efficiency of GO nanosheets for CA was reduced at pH >4 and enhanced at pH <4 in the presence of HA.

In order to assess correctly the gases emissions from oil/gas field water and its contributions to the source of greenhouse gases (GHG) at the atmospheric temperature and pressure, a simulation experiment was first developed to study the natural emissions of GHG into the atmosphere in the southern gas field, Sichuan Basin, China. The result showed that methane (CH₄) and carbon dioxide (CO₂) were the two gases that released from the gas field water. Time and temperature played important roles in GHG emissions, and the higher temperature was found to enhance carbon emissions. Under the lower/intermediate temperature conditions (5 and 15 °C), majority of gases were released from the gas field water during the first 2 h, whereas under the higher temperature conditions (30 °C), the majority of gas released from the gas field water continued for 12 h. By dividing the whole emission duration into six time durations (one time duration was 12 h), we calculated the fluxes of CH₄and CO₂. The substantial variation in the gas fluxes reflected that the cumulation of time also played a crucial role in the process of GHG emissions. In the first emission duration (0–12 h) at 30 °C, the maximum fluxes of CH₄and CO₂were 1.47 and 1.87 g/m³·h, respectively. The values were obviously higher than those in other durations, so were the fluxes shift in different durations at 5 and 15 °C. Additionally, we found that the emissions released from the gas field water which came from overpressure formation formed higher carbon emissions.

Textile industry is responsible for a large amount of polluted water released daily, mainly due to the dyes used. This article has aimed to study and improve methodologies for degrading textile effluents containing the dyes Acid Red 151 and Acid Blue 40 using an electrolytic reactor. Different solutions were prepared for the experiments in the electrolytic reactor with a 70 % TiO₂/30 % RuO₂anode. The textile effluents underwent 0 (control), 3, and 30 min treatment intervals. A suspension of Saccharomyces cerevisiae cells was used for toxicity tests and performed at the same day that samples were collected. The same test was applied to the samples after 15 days resting in order to verify changes in toxicity. The electrolytic treatment successfully removed the color in all effluents. However, the process efficiency varies according to the dye used and the experimental conditions, such as current and NaCl concentration. Also, it was observed that treatments longer than 30 min are very toxic to S. cerevisiae cells because of the high concentration of Cl₂.

Adsorption and removal of cadmium ions from simulated industrial wastewater using hydrophilic and hydrophobic commercial silica nanoparticles are reported. These results are compared with those obtained using sol–gel silica nanoparticles. Two types of dense commercial pyrogenic silica nanoparticles with different chemical groups on the surface were used to adsorb cadmium ions: Aerosil A130VS and R972. The pore absence in these particles reduces the surface area and, consequently, the concentration of active chemical groups appropriated for adsorption, as compared with the sol–gel particles that are highly porous; this effect is partially compensated by the small sizes available for these commercial particles. The concentration of cadmium ions was reduced: from 109 to 0.01 ppm for A130VS, from 138 to 1.44 ppm for R972, and from 123 to 0.005 ppm for sol–gel. The flocculation kinetics was obtained using dynamic light scattering and the amount of adsorbed cadmium in the sediment using atomic absorption spectroscopy.

Filtration can be a convenient technique for removing phosphorus (P) at on-site wastewater treatment facilities to recycle this non-renewable element. When testing potentially suitable materials for these filters, the properties of the influent and the method used to analyse measured effluent concentrations both affect the P binding capacity determined in filter tests and therewith filter longevity predictions. At present, there is a lack of robust methods for material investigation and filter test interpretation. This study was conducted to investigate the effect of inflow PO₄–P concentrations (concentration) and hydraulic surface load (load) on P binding capacity and to analyse possible interpretations of laboratory filter tests. A 2²factorial experiment with replicates was performed on the calcium-based filter material Filtra P. The investigated concentrations ranged from 12 to 50 mg L⁻¹and loads from 419 to 1,023 L m⁻² day⁻¹. P binding capacity (calculated by mass balance including data until PO₄–P breakthrough point) was negatively affected by concentration and positively affected by load, with the effect of concentration being slightly greater. Depending on the factors' settings and on the method of evaluation (i.e. analysing all pre-saturation data or considering only pre-breakthrough results), the total measured P binding capacity varied between 2.2 and 9.0 g kg⁻¹. The part of the breakthrough curve between the breakthrough point and saturation contributed significantly to the measured P binding capacity, and it took about three times longer for the filters to become saturated than to reach breakthrough. Furthermore, a considerable amount of P that had reacted with the filter material was washed out of the filters as particle-bound P. This indicates that it is important to determine both the PO₄–P and the particle-bound P phases in the filter effluent.

The paper reports ultraviolet matrix-assisted laser desorption/ionization mass spectroscopy (UVMALDI-MS) protocol for determination of complex heterogeneous emulsion or suspension formulations. The active agents and surfactants are morpholine fungicide fenpropimorph (1), amorolfine (2), tridemorph (mixture of 2,6-dimethyl-4-alkylmorpholins 3–6), 2,6-dimethyl-4-[2-methyl-3-(6-methyl-decahydro-naphthalen-2-yl)-propyl]-morpholine (7), dodemorph (8), main metabolite of 1 fenpropimorph acid (9), sodium dodecyl sulfate (10), and stearate (11). The full method and techniques validation as well as method performance parameters are discussed in terms of their maximal representativeness toward real environmental and foodstuff assay problems. These are additionally complicated by heterogeneous laterally, vertically, and time distribution of pesticide contaminants and their major metabolites in environmental samples. The real environmental heterogeneous distribution is elucidated, studying sterilized soil fractions with particle size 2.0 μm, clay content 11.5 %, silt 23.0 %, sand 8.1 %, and pH ∈ 6.0–8.1. A statistical sampling cluster approach is used. The method performance parameters are concentration LODs of 0.026 mg kg⁻¹(res. LOQs 0.08666 mg kg⁻¹). Concentration linear dynamic ranges are ∈ 0.025–7.3 mg kg⁻¹(r² = 0.99822 and 0.99421) and ∈ 2.3–7.4 mg kg⁻¹(level of confidence of 99.33₁ %) for complex spiked heterogeneous soil samples. The data illustrates the great capability of method and its promising application for environmental contamination monitoring and controlling programs for assessment.

Passive air samplers were deployed at six locations across the province of Manitoba, Canada, to represent areas with, or at various distances from, agricultural herbicide applications. During the growing seasons in 2008 and 2009, the four southern sites always demonstrated mixtures of current-use herbicides (CUHs) in air, but CUHs were not detected at the two northern sites that were 400 and 800 km away from Manitoba’s most northern boundary of agricultural herbicide applications. The masses of the CUHs detected in the air were most strongly positively associated with their estimated masses typically applied in a ~100-km²township area surrounding the sampling sites (r = 0.70 to 0.74) and to a lesser extent with their estimated mass applied in incrementally larger areas (r = 0.53 to 0.59). The masses of CUHs detected in air were also significantly positively associated with their estimated masses applied at a provincial level (r = 0.45 to 0.52) but not with their reported half-lives in air, suggesting that a system of maintaining records of herbicide use data, even at a coarse scale, can strongly improve agri-environmental risk assessments. Of the nine CUHs detected, MCPA [(4-chloro-2-methylphenoxy)acetic acid] and bromoxynil, which are widely applied in Manitoba agriculture, were the only herbicides detected at all four southern sites. Triallate and metolachlor which have low use in Manitoba were the only CUHs detected in the winter months, confirming that these herbicides are relatively persistent in the air and may undergo long-range transport. Four passive air samplers, each installed 0.5 to 1.5 km apart at the same location, showed variations in the herbicide masses detected with the coefficient of variation ranging from 10 % for bromoxynil in 2008 to 137 % for MCPA in 2009. These variations were particularly observed not only for the two herbicides applied on-site (MCPA and clopyralid) but also for four herbicides transported into the area from longer distances (2,4-D (2,4-dichlorophenoxyacetic acid), bromoxynil, ethalfluralin, and triallate). Future regional-scale research should therefore consider deploying multiple sets of passive air samplers at a site to obtain a more representative measure of herbicide air concentrations.

Effect of biochar, derived from unfertilized dates, on the immobilization of Cd and Ni, in a sandy loam alkaline soil, was investigated. The biochar was applied to the soil columns at the rate of 0.5, 1, and 2 % (w/w) artificially polluted with 10 mg kg⁻¹Cd and 100 mg kg⁻¹Ni. After 1 month incubation of soil-biochar mixture under ambient conditions, the soil bulk density was reduced by 0.19 g cm⁻³as compared with no biochar addition with increase in soil pH. A reduction of 53 % in the NH₄NO₃-extractable soil Ni was recorded as compared with the corresponding control without biochar addition. After incubation, the water-soluble Ni and NH₄NO₃-extractable soil Cd and Ni contents were significantly lower in all the biochar treatments than the control. A reduction of 53 % in the NH₄NO₃-extractable soil Ni was recorded as compared with the corresponding control. The biochar content separated from the incubated soil showed low concentrations of NH₄NO₃-extractable Cd and Ni. The total Ni and Cd contents recovered from biochar samples after incubation were 35.2 and 3.7 mg kg⁻¹, respectively. Their contents in soil were substantially reduced by the incorporation of biochar amendment (114 to 57.2 mg kg⁻¹Ni, 9 to 5.6 kg⁻¹Cd) as compared with the no-biochar control. Therefore, addition of the biochar improved the soil physical properties and succeeded in immobilizing the studied metals.

In this study, Scenedesmus quadricauda ABU12 was immobilized with sodium alginate to determine its potential for decolorizing indigo blue dye under different incubation conditions. The microalga was incubated at different pH (6.5–9.5), biomass concentrations (0.1–1.0 g l⁻¹), dye concentrations (12–75 mg l⁻¹) and temperatures (25–40°C). The concentration of biomass used significantly determined the rate of dye decolorization, as the lowest biomass concentration (0.10 g) was able to completely decolorize the dye by day 3, while the highest biomass concentration (1.00 g l⁻¹) attained 100 % decolorization on day 4. Neutral pHs supported the highest dye decolorization rates compared alkaline pHs. The rate of dye decolorization had a linear relationship with the concentration of the dye in solution as increasing dye concentration in the medium significantly reduced the rate of decolorization (p < 0.05). At 25°C, the rate of dye decolorization was consistently higher from day 2 to the end of the experiment. Infra-red analyses of the algal biomass and the dye solution was done in Kbr by pressing between flat aperture plates of sodium chloride and scanning from 4,000 to 625 cm⁻¹. This revealed the presence of functional groups associated with the biomass and dye that provided possible explanations for the decolorization of the dye under the different incubation conditions. These results showed that immobilized S. quadricauda is capable of decolorizing indigo blue dye at low biomass when immobilized with sodium alginate. However, this was dependent on the incubation temperature and dye concentration.