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.

We report on treatment and disposal of flue gas desulfurization (FGD) as a solid and hazardous waste. The effects of modified flue gas desulfurization residue (MFGDR) prepared by calcining a mixture of dry/semi-dry FGD residue, potassium feldspar, and/or limestone power on growth of plant and soil amelioration are investigated. The effect of MFGDR on the sweet potato was evaluated by analyzing the soil physiochemical properties and heavy metal speciation in the soil, and the yield, quality, and heavy metal concentrations of the sweet potato. The results indicated that applying MFGDR as soil ameliorant increased total yield by 53.38 %, safety, and the quality of sweet potato. The concentrations of Cd, Cr, Cu, Pb, and As in the sweet potato reduced by 31.34, 70.57, 22.17, 79.49, and 100 %, respectively. The improvements were attributed to enhancement of soil mineral composition contained in MFGDR. The MFGDR could also improve the soil physicochemical properties and decreased phytoavailability of heavy metals. The application of MFGDR in agriculture not only was a potential and useful technique for recycling and utilization of FGD residue, but also had potential benefits for soil amelioration, plant growth, and decrease of heavy metals in grown products.

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.

Advanced wastewater treatment with granular activated carbon (GAC) is a promising option to reduce emissions of organic micropollutants (OMP) into the aquatic environment. Frequent back-washes of the GAC filters are required due to high particle concentration in the treated wastewater but lead to stratification. Differences in adsorption capacities of individual strata are not known. The present study aimed at investigating physical and chemical differences at different filter depths of a stratified GAC filter. Two different commercial products were stratified during repeated filter bed expansions and sectioned into vertical fractions. Bulk densities, grain size distributions and ash contents of the individual fractions differed significantly. Adsorption tests with pulverized GAC from different levels showed great vertical differences in adsorption properties. OMP removals determined in the upper part of a GAC filter therefore cannot be extrapolated downwards. Both physical and chemical vertical heterogeneities with regard to adsorption capacities and residence times at different filter depths should be considered in the filter design, in the monitoring of a GAC filter, and in the interpretation of the GAC filter performance. Good correlations between abatements of UV light absorption and OMP removals were found for the virgin GAC throughout the non-uniform filter.

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.

Tremendous surge in the industrialization and infrastructure development worldwide have led to a significant rise in environmental pollutants in the last 2–3 decades. Pollutants in the natural environment consist of highly diversified and complex mixtures. A single biomarker cannot be used to assess a complete identification of environmental pollutants. In this context, it is highly recommended by environmental scientists to evaluate a set of complementary biomarkers for the complete assessment of toxic burden of complex environmental pollutants in the exposed organisms. Moreover, a multiple biomarker approach for the stress assessment is believed to have high sensitivity and could be done in comparatively lesser measuring time. The present article focuses on the viability of usage of xenobiotic detoxification enzymes viz. phase I and II as the toxicity biomarkers. As far as our knowledge goes, we are for the first time reporting phase I and phase II enzymes together as potential toxicity biomarkers in a single article.

Microalgae-based bioremediation processes pose dual abilities of simultaneous CO₂ fixation through photosynthesis and degradative effect on environmental pollutants. This study intends to investigate the tolerance and biodegradation capability of Spirulina maxima for removal of phenol. An assimilation study of the phenol-carbon was also conducted to elucidate if the phenol removal was dominated by physical adsorption on cell walls or through metabolic activities. S. maxima cells were found to be capable of growing on phenol up to a concentration of 400 mg l⁻¹, and they had a highest specific growth rate at a phenol concentration of 50 mg l⁻¹. The results suggested that the removal of phenol (as high as 97.5 %) was mainly due to biodegradation processes rather than a bioadsorption process. Moreover, it was evident that nearly 30 % of the ¹³C-labeled phenol content was discovered in the cellular fraction, indicating that the ¹³C-phenol-carbon was indeed assimilated to biomass followed by mineralize the carbon to CO₂.

Natural (AC-N) and electrochemical iron-modified activated carbon (AC-Fe-2.5A) were applied to treat wastewater with organic by-products generated by the manufacture of acrylic resins from methyl methacrylate (MMA) using batch and column systems. MMA wastewater has an extremely complex composition with a chemical oxygen demand concentration of 651.25 g O₂/L, total organic carbon (TOC) concentration of 227.86 g/L, NH₄⁺concentration of 62.74 g/L, and 352,500 PtCo units. Wastewater was distilled to decrease the ammonium concentration with a removal efficiency of ammonium of 52 %. Then, Fenton oxidation was applied in order to promote the partial oxidation of organic matter; the molar dosage of Fe²⁺/H₂O₂was 0.018/5.700 at pH 5.3. After distillation and oxidation processes, batch experiments using natural and iron-modified activated carbon were carried out in order to determinate the adsorption equilibrium time and capacities. The global removal percentages of TOC by oxidation–adsorption treatment were the highest at pH 2, 21.09 and 29.46 % for AC-N and AC-Fe-2.5A, respectively, and for color were most efficient at pH 4, 80.62 and 72.55 % for AC-N and AC-Fe-2.5A, respectively. The results showed that AC-Fe-2.5A was more efficient than AC-N for the removal of TOC. The electrochemical modification improves the adsorption capacities and properties of activated carbon.

Solid organic carbon and zero-valent iron (ZVI) have been used separately as reactive media in permeable reactive barriers (PRBs) to degrade nitrate in groundwater, but few studies have examined the combination of the two materials in one system for nitrate remediation. In the present study, batch tests are conducted to evaluate three common solid organic carbons and their combination with ZVI for nitrate removal from water. The results show that the combined system achieves better denitrification efficiency than that measured with sawdust or cotton alone. However, no obvious difference is noted between the cornstalk alone and its mixture with ZVI treatment. When complete nitrate removal is achieved in the system that combined ZVI with sawdust or cotton, only 72 and 62.6 % of nitrate removal, respectively, are obtained in which the carbon (C) source is used alone. The results indicate that there are synergistic effects in the combined denitrification system, and the effects depend on the type of carbon material used. Sawdust is an alternative carbon source for nitrate removal in a C-ZVI-combined system. In a sawdust-ZVI system, the accumulation of nitrite and ammonium is affected greatly by nitrate concentration, C/N ratio, and Fe/N ratio.