In two soils from Central Greece, a pot experiment was conducted with the addition of mixture at various ratios of zeolite and compost (based on Posidonia oceanica (L.) leaves) applied at a rate of 5% w/w (calculated on a soil dry weight basis). Three varieties of tobacco (Burley, Virginia, and Oriental) were cultivated, and Cu, Zn, and Cd concentrations in tobacco leaves were measured at first, second, and third primings. We found that the addition of zeolite in the soil1 led to a significant reduction of metal concentration in all three tobacco varieties compared to the control. Also, zeolite addition reduced significantly the water-soluble, as well as, DTPA-extractable metal concentrations, compared to the other treatments. Our results suggest that the most effective amendment in soil 1 was the mixture consisting of 20% compost and 80% zeolite; this mixture led to higher reduction of metal concentration in all tobacco varieties. As for soil 2, which had almost twice as high Cd concentrations as than in soil 1, Posidonia compost was more effective in reducing Cd concentrations from all three tobacco varieties. In all cases studied, both in soils 1 and 2, Cd concentration was higher in Burley tobacco leaves. The results indicate that a mixture of zeolite and compost consisting of Posidonia oceanica (L.) is a low-cost soil conditioner that is effective in reducing tobacco Cu, Zn, and Cd uptake.

A set of chitosan-g-poly(acrylic acid)/rice husk ash hydrogel composites was successfully employed as methylene blue (MB) adsorbent. Maximum MB adsorption capacity of 1952 mg/g of dried hydrogel was obtained with the composite at 5 wt% of rice husk ash (RHA) at pH ≥ 5. The adsorption capacity varied from 1450 to 1950 mg/g with increasing the initial MB concentration from 1500 to 2500 mg/L. The MB removal efficiency was higher than 90% for all samples. At pH ≥ 5, negatively charged groups (–COO⁻) in the adsorbent were generated, which could strongly interact with the positive charges from MB, favoring adsorption. Adsorption kinetics followed the pseudo-second-order model, which is based on the chemisorption phenomenon, reaching saturation as fast as 1 h of experiments due to the formation of an adsorbed MB monolayer, as suggested by the Langmuir isotherm model (type I). Desorption experiments showed that 75% of loaded MB can be removed from the adsorbent by immersing it in a pH 1 solution. CHT-g-PAAc/RHA5% composite was submitted to five cycles of adsorption/desorption, maintaining its MB removal efficiency at 91%. Therefore, chitosan-g-poly(acrylic acid)/RHA hydrogel composites present outstanding capacity to be employed in the remediation of MB-contaminated wastewaters.

An innovative diatomite-supported iron catalyst has been developed by using an impregnation process with a mixture of ferrous (Fe²⁺) and ferric (Fe³⁺) ions in the form of precipitated iron hydroxides. Raw and modified diatomite samples have been characterized by X-ray fluorescence and scanning electron microscopy. The main characterization results have revealed that modified diatomites are amorphous and have higher iron concentrations than raw diatomite. The results also indicate that the modified materials provided significant catalytic activity on phenanthrene degradation by using sodium persulfate. Satisfactory results were obtained with 45 g/L of sodium persulfate and 1 g of modified diatomite, thus degrading 98% of phenanthrene during 168 h of treatment. Kinetic and statistical approaches were developed for the remediation process herein, which have been validated with experimental data, thence yielding suitable results.

Air pollution represents a significant fraction of the total mortality estimated by the World Health Organization (WHO) global burden of disease project (GBD). The present paper discusses the characteristics of trace gases (O₃, NO, NO₂, and CO) and particulate matter (PM₁₀ and PM₂.₅) in two Asian megacities, Delhi (India) and Beijing (China). A continuous measurement of trace gases and particulate matter are considered from 12 measuring sites in Beijing and 8 sites in Delhi. Over Beijing, the annual average of PM₂.₅, PM₁₀, O₃, NO₂, and CO is, respectively, 85.3, 112.8, 58.7, and 53.4 μg/m³ and 1.4 mg/m³, and, respectively, over Delhi 146.5, 264.3, 24.7,and 19.8 μg/m³ and 1.73 mg/m³. From the spatial variations of pollutants, the concentrations of particulate matter and trace gases are observed to be much higher in the urban areas compared to the suburban areas. The higher average concentrations of PM₁₀ and PM₂.₅ over Delhi and Beijing are observed during winter season compared with other seasons. The maximum diurnal variation of PM₁₀ concentration is observed during winter season over Beijing and Delhi. The comparison of trace gases shows that the O₃ concentrations during daytime are obviously higher compared with nighttime, and the highest diurnal variation of O₃ is observed during summer. The concentrations of CO are highest during winter season, and higher concentrations are observed during nighttime compared to daytime. The O₃ and CO show negative correlation over Beijing and Delhi. The negative correlation between O₃ and NO₂ is merely observed over Beijing, while CO and NO₂ concentrations, in contrast, show positive correlation over Beijing.

In the present study, the ability of Hibiscus rosa-sinensis leaf extract (HLE) to act as a natural coagulant for the water treatment was tested. Synthetic turbid solutions were prepared using kaolinite, and the efficiency of HLE was examined for low and high turbid solutions. HLE was very effective in high turbid solutions than in low turbid water and follows enmeshment mechanism of destabilization. An insignificant effect of alkalinity on the performance of HLE was observed. The addition of NaCl increased the dissolution of coagulation active species and enhanced the efficiency of HLE, significantly. Hydroxyl and carboxyl groups present in HLE were the major functional groups responsible for the bonding between coagulant and kaolinite. The efficiency of alum was very high compared to that of HLE in both turbid solutions. But the optimal dosages of HLE were lesser than that of alum. Thus, HLE can be used as a coagulant aid for the effective treatment of water.

The Highveld and Waterberg regions in South Africa contain extensive coal fields and therefore have a high concentration of coal-fired power stations. Previous studies assessed the impact of atmospheric deposition of S- and N-containing species from anthropogenic sources in the region but did not include the effect of biogenic emissions. This study models biogenic NOX soil emissions for the regions and includes them in an atmospheric dispersion model to study the effects of biogenic emission on nitrogen deposition rates. Simulated sulfur deposition rates for the Highveld area are also reported on. Anthropogenic and biogenic sulfur and nitrogen emission sources were inventoried for the Highveld and Waterberg regions. Using previous work by Yienger and Levy, biogenic soil NOX emissions were quantified by constructing models for both areas using land use data, rainfall data, and atmospheric ground level temperatures from CALMET data. A CALPUFF dispersion model was used to predict deposition rates for S- and N-containing species with and without biogenic NOₓ emissions to determine the impact of biogenic emissions for the Highveld. As rainfall is highly variable in the region, meteorological data representative of high, average, and low rainfall years was used to determine the effect of rainfall on deposition rates for the various species. The biogenic NOₓ made up 3.96, 4.14, and 3.34% of total released NOₓ for 2001 (average rainfall), 2003 (low rainfall), and 2010 (high rainfall), respectively. Dry nitrogen deposition rates were affected most by the biogenic component, adding from 1.7 to 6.2% at various receptor locations. Wet deposition rates were affected very little (0.13 to 0.75%). Effect on total nitrogen deposition rates ranged from 0.32 to 1.77%. Biogenic emissions for the Waterberg area, being more arid, were calculated to be only 2.3% of total NOₓ emissions for the area and accordingly have little effect on deposition rates.

The micro/mesoporous composite ZSM-5/KIT-6 was synthesized via the assembly procedure of preformed ZSM-5 seeds into mesostructured KIT-6, and mechanical mixtures with different contents of zeolite were prepared via a mechanical grinding procedure. These composites were used as adsorbents for the capture of CO₂ in the simulated flue gas conditions of 60 °C and 15 vol% CO₂ with a thermal gravimetric analyzer (TGA). The combination of dual-pore structures improved the adsorption performance. The composite synthesized via the assembly procedure exhibited superior adsorption capacity to the mechanical mixtures. The maximum adsorption capacity was 1.223 mmol/g. For mechanical mixtures, the adsorption capacity was dependent on the ZSM-5 content and increased with the increase of ZSM-5 content. The composite can be applied for CO₂ adsorption at flue gas temperature and desorption at regeneration temperature of 110 °C. The adsorption capacity showed only 3% attrition during five consecutive cyclic adsorption/desorption tests. The composites displayed excellent CO₂ adsorption/desorption performance.

Aluminum/iodine pentoxide (Al/I₂O₅) composites are currently receiving much attention for their capabilities as potential anthrax combatants. Their high halogen gas release, coupled with high temperature evolution from combustion, renders them effective in bacterial deactivation. Despite extensive research on the energetic capacities of these compounds, limited information is currently available in relation to their potential environmental (non-target) effects. We evaluated the effects of Al/I₂O₅ on aquatic (Daphnia magna) and terrestrial (Eisenia fetida, Acheta domesticus) invertebrates, as well as alfalfa (Medicago sativa) seed germination. Polytetrafluoroethylene (PTFE, or DuPont Teflon® MP1150) was examined concurrently to assess whether observations were general to halogen, or element specific. Our observations were based on mortality and reproduction (hatchability) for the terrestrial and aquatic assays. In all Al/I₂O₅ assays, mortality was concentration dependent, ranging from 0% mortality in the control samples to partial and complete mortality in the contaminated cases. The PTFE assays showed no mortality at all contaminant concentrations. At a maximum Al/I₂O₅ contaminant concentration of 1000 μg/g (ppm), 100% mortality was observed in cricket assay conducted in sand within 72 h exposure and earthworm assay conducted in soil within 4 days exposure. In the aquatic assay, a water concentration of 200 μg/mL (ppm) caused 100% mortality to D. magna in less than 12 h. The effect of aluminum/iodine pentoxide on earthworm cocoon hatching success was also determined. At soil concentrations ≤ 400 μg/g, hatching success for earthworm cocoons was equivalent to control (un-contaminated) soil; above this concentration, hatching success was reduced by a factor of 2. Alfalfa germination tests were performed at a single contaminant concentration of 1000 μg/g. This soil concentration was completely inhibitory to seed germination.

The research comprised of studying the effect composting sewage sludge with sawdust and vermicomposting with earthworm Eisenia fetida has on the degradation of 16 polycyclic aromatic hydrocarbons (PAHs). Raw rural sewage sludge prior composting was more contaminated with PAHs than urban sewage sludge, in both cases exceeding EU cutoff limits of 6 mg/kg established for land application. Dibenzo[a,h]anthracene (DBahAnt), acenaphtylene (Acy) and indeno[1,2,3-c,d]pyrene (IPyr) were predominant in rural sewage sludge, whilst the urban sewage sludge contained the highest concentrations of benzo[b]fluoranthene (BbFl), benzo[k]fluoranthene (BkFl) and indeno[1,2,3-c,d]pyrene (IPyr). Thirty days of composting with sawdust has caused a significant reduction of 16 PAHs on average from 26.07 to 4.01 mg/kg (84.6%). During vermicomposting, total PAH concentration decreased on average from 15.5 to 2.37 mg/kg (84.7%). Vermicomposting caused full degradation of hydrocarbons containing 2 and 6 rings and significant reduction of PAHs with 3 aromatic rings (94.4%) as well as with 5 aromatic rings (83.2%). The lowest rate of degradation (64.4%) was observed for hydrocarbons with 4 aromatic rings such as fluoranthene, benzo(a)anthracene, chrysene and pyrene. On the other hand, the highest level of degradation was determined for PAHs with 2 rings (100%), 3 rings (88%) and 6 aromatic rings in the molecule (86.9%) after composting with sawdust. Acenaphthene and pyrene were found to be the most resistant to biodegradation during both composting methods.

Regular monitoring of key water quality parameters is important for assessing the hydrological status of a lagoon and its management activities. In this study, a new cost-effective technique based on the geo-ecological information-modeling system (GIMS) is implemented employing the combined use of simulation experiments and in-field observations to investigate the problem of optimizing water quality monitoring of a lagoon. The GIMS is accompanied by 39 elements selected in 8 management systems and 31 functional elements, which are described in detail. It is shown that the combined use of model and field observations allows reliable recording of lagoon water quality and optimization of the monitoring regime. Finally, simulation experiments are presented, demonstrating the fidelity of the proposed modeling system to optimize water quality control through regular in-field measurements and simulations.