Adsorption by low-cost adsorbents and biosorbents is recognized as an effective and economic method for low-concentration heavy metal. The purpose of this study was to investigate the possibility of the utilization of N,N′-bis(2, 5-dihydroxybenzylidene)-1, 4-diaminobenzene (DHDB)-immobilized sporopollenin (Schiff base-immobilized sporopollenin, Sp-DHDB) as a sorbent for removal of lead (II) ion from aqueous solution. The effects of different parameters (such as sorbate concentration, sorbent dosage, and pH of the medium) were investigated by differential pulse anodic stripping voltammetry (DPASV) technique. The experimental data were analyzed by the Freundlich, Langmuir, and Dubinin–Radushkevich (D–R) isotherms. Equilibrium data fitted well with the Freundlich model and the procedure developed was successfully applied for the removal of lead ions in aqueous solutions. This investigation reveals a new, simple, environmentally friendly, and cost-effective method for the removal of lead ions from aqueous solutions by a new Sp-DHDB material.

The processes affecting adsorption of molybdenum (Mo) in alkaline industrial soils are not well known, as most research on Mo fate and transport has focused on agricultural soils. In this work, we performed studies of soil extraction, as well as sorption studies using both batch and stirred-flow cell approaches. After 60 h of extraction, we observed, even where three extractable fractions were present, 14.1 % of the bound residue was extracted by CaCl 2 solution. This indicates that the procedures recommended by the Commission of European Communities Bureau of Reference, which is targeted to metals cations, not anions due to the use of extractants at acidic pH, are not a suitable approach for assessing mobility and availability of Mo in alkaline soils. Because the observed extent of Mo adsorption onto two Fe minerals, goethite, and amorphous iron hydroxide (HFO) was 2 to 3 orders of magnitude higher than that onto the soil, soils amended with these Fe minerals were found to have a higher Mo adsorption capacity, with HFO yielding stronger sorption than goethite. The additivity principle was successfully used to predict Mo adsorption with the HFO-amended soil but failed to do so for the goethite-amended soil. The best fit sorption isotherms and estimated parameters were slightly different from batch and flow cell experiments. The Kd values of sorption coefficient in our industrial soils and Fe-minerals-amended soils ranged from 0.19 to 1.45 L/kg from both experimental approaches; this low adsorption potential renders it infeasible to immobilize Mo into the soilmatrix and reduce Mo availability by amending the soil with Fe minerals. In the future, materials with potentially high Mo adsorption capacities should be identified, screened, and characterized for permeable reactive barriers application. © Springer Science+Business Media Dordrecht 2013.

Textile dye Victoria Blue-B (VB-B) was approached in two different ways: one to get rid of the color for its easy disposal to the environment, and the other is to reuse the decolorized water for coloring the same dye. Shewanella decolorationis (MBTD16) isolated from Dona Paula Bay, identified by 16S rRNA gene and its action over decolorization was monitored by Fourier transform infrared spectroscopy, UV–Vis spectrum, and a color scanner. Dye removal index increased L*, a*, and b* to 91.585, −2.856, and −0.132 against 62.29, −4.93, and −20.75 within 42 h as a first report. A maximum extent of decolorization (94.83 %) could be achieved with minimum dye concentration of 50 mg L⁻¹. The colored water treated by free and immobilized bacterial cells tested to reuse (VB-B dye) could give 35–50 % more color than the original. Process parameters optimized to achieve maximum decolorization indicated pH 7, temperature 32 ± 2 °C, inoculum size 8 % with co-substrates of glucose and yeast extract 5 g L⁻¹ for its supremacy. Synthesis of lignin peroxidase and tyrosinase augmented in strain S. decolorationis only after being exposed into the dye signifies the enzymes in decolorization, and it was confirmed through one-way ANOVA. Results obtain by this work could suggest that S. decolorationis can be used very well to decolorize the textile dye, and the same water could be recycled to get back its original color by adding around half the quantity of dye. Thus, by the use of water, dye and pollution levels could be minimized.

The photooxidation degradation of tri (2-chloroethyl) phosphate (TCEP) by combining UV with hydrogen peroxide as oxidant was primarily studied in the present study by evaluating various treatment parameters. The results suggested that light intensity, initial pH and concentration of TCEP and H₂O₂, and reaction time affected the degradation efficiency of TCEP. The total organic carbon (TOC) removal rates, and the yield rates of Cl⁻and PO₄ ³⁻reached up to 86 %, 94 % and 97 %, respectively, under the optimized conditions in the present study. The degradation process obeyed the pseudo-first-order kinetic reaction expressed as ln (C ₜ/C ₀) =−0.0275 t with a R ² of 0.9962. The addition of t-butanol indicated that hydroxyl radicals played an important role in the degradation of TCEP. The primary investigation of the degradation mechanism of TCEP suggested that TCEP molecules were attacked by hydroxyl radicals produced from H₂O₂ with the irradiation of UV light, PO₄ ³⁻, Cl⁻and chlorinated alcohol/aldehyde, and/or non-chlorinated aldehyde with small molecular weight were produced, these produced small organic molecules were furthered oxidized to acids, most of them were finally mineralized to CO₂ and H₂O. The present technology was successfully applied for degrading TCEP in simulated real wastewater, which shows a promising potential for treating similar contaminants using corresponding advanced oxidation technology.

Radionuclide and heavy metal contamination influences the composition and diversity of bacterial communities, thus adversely affecting their ecological role in impacted environments. Bacterial communities from uranium and heavy metal-contaminated soil environments and mine waste piles were analyzed using 16S rRNA gene retrieval. A total of 498 clones were selected, and their 16S rDNA amplicons were analyzed by restriction fragment length polymorphism, which suggested a total of 220 different phylotypes. The phylogenetic analysis revealed Proteobacteria, Acidobacteria, and Bacteroidetes as the most common bacterial taxa for the three sites of interest. Around 20-30 % of the 16S rDNA sequences derived from soil environments were identified as Proteobacteria, which increased up to 76 % (mostly Gammaproteobacteria) in bacterial communities inhabiting the mine waste pile. Acidobacteria, known to be common soil inhabitants, dominated in less contaminated environments, while Bacteroidetes were more abundant in highly contaminated environments regardless of the type of substratum (soil or excavated gravel material). Some of the sequences affiliated with Verrucomicrobia, Actinobacteria, Chloroflexi, Planctomycetes, and Candidate division OP10 were site specific. The relationship between the level of contamination and the rate of bacterial diversity was not linear; however, the bacterial diversity was generally higher in soil environments than in the mine waste pile. It was concluded that the diversity of the bacterial communities sampled was influenced by both the degree of uranium and heavy metal contamination and the site-specific conditions. © 2013 Springer Science+Business Media Dordrecht.

Several studies related to zero-valent iron (ZVI), which is employed for water remediation, have been made during the last years. It was found in the literature that the tests made with ZVI in situ, especially for groundwater remediation, were performed using ZVI and nano zero-valent iron (nZVI) as well. Particles usually are used like a “trench-and-fill” installation. In this arrangement, ZVI or nZVI is disposed in the contaminated areas, applied alone or mixed with other materials. The aim of the current work is to evaluate the use of nZVI, which is synthesized in laboratory, for copper ion removal in aqueous solution. The present study will serve like a base focusing, in a future stage, on the use of nZVI on groundwater remediation. For this purpose, commercial ZVI particles were also tested in order to compare the removal behavior. During this study, a relation between the solution characteristic (pH, ion concentration) and the surface purity of the iron particles was found. This relation generally is not reported in the literature. Finally, the copper removal was satisfactory with ZVI and nZVI.

This paper provides a short overview of the main oxidation processes more commonly applied for the remediation of contaminated sites, with specific reference to their application for the in situ remediation of contaminated sites, i.e. In Situ Chemical Oxidation (ISCO). A review of the main patents issued on this topic shows the relevant contribution to the development of this technology in the last 20 years, especially in the USA. The still limited deployment of ISCO in other geographical areas may be improved by the increased acceptance of the technology that may come from the development of proper application guidelines based on accepted design criteria. The latter ones are also discussed in this paper with reference to the application of Fenton's treatment. © 2013 Springer Science+Business Media Dordrecht.

Surfactant-enhanced solubilization and subsequent biodegradation of phenanthrene and pyrene from aqueous solutions by Arthrobacter strain Sphe3 was investigated. The results show that growth of Arthrobacter strain Sphe3 was increased upon increase in concentration of Tween 20 and Tween 80. Inhibition of bacterial growth was observed with increasing Triton X-100 concentrations, whereas sodium dodecyl sulfate (SDS) totally inhibited this bacterial growth. Phenanthrene and pyrene solubilization was enhanced in the presence of surfactants and found to be linearly proportional to their concentrations, above the critical micelle concentration (CMC). In addition, Tween 20 and Tween 80 enhanced the biodegradation of phenanthrene and pyrene. The high correlation coefficient (R ²) values obtained at all the concentrations studied, suggest that biodegradation kinetics of both phenanthrene and pyrene in the presence of Tween 20 and Tween 80 follow first-order kinetic equation model. Experimental results suggest that Tween 20 and Tween 80 may have great potential for applications in bioremediation of these polycyclic aromatic hydrocarbon (PAH) compounds using Arthrobacter strain Sphe3.

Static granular bed reactor (SGBR) and upflow anaerobic sludge blanket (UASB) reactor were demonstrated at mesophilic condition for the treatment of pulp and paper mill wastewater. The hydraulic retention times (HRTs) were varied from 4 to 24 h following 29-day start-up period. The overall chemical oxygen demand (COD) removal efficiency of the SGBR was higher than the UASB during this study. At 4 h HRT, the COD removal was greater than 70 % for the SGBR and 60 % for the UASB. Biomass yield and volatile fatty acids concentration of SGBR were slightly less than UASB at organic loading rates ranging from 1.2 to 5.1 kg/m³/day. The results indicated that the SGBR system can be considered a viable alternative system for anaerobic treatment for pulp and paper wastewater.

Volatile organic compounds (VOCs) are ubiquitous in marine areas in many parts of the world. Effect of environmental factors (light intensity, temperature, oxygen levels, and presence of sensitizer) on photodegradation of VOCs present in water-soluble fraction of Kuwait crude oil was investigated in laboratory conditions. The results showed that all factors investigated had significant effects on photo degradation rates. Higher temperatures produced faster degradation rates. At 15 °C, most of the volatile optimally degraded when light intensity was set at 750 W/m². Oxygen level of 7 ppm and presence of sensitizer was also required. Oxygen level of 4 ppm and light intensity of 500 W/m² and presence of a sensitizer produced optimal degradation rates for most of the compounds at 30 °C. At 40 °C, deoxygenated water-soluble fraction and light intensity of 500 W/m² produced the fastest degradation for many of the volatile compounds. Linear regression indicated that for most of the compounds temperature had the greatest effect on degradation rates.