Heavy metals are causing serious environmental and health problems worldwide, especially in places where mining is one of the major drivers of the country’s economy. Conventional technologies are considered expensive when providing the safe water; for this reason, new clean water technologies are needed. Biosorption has gained attention as a cost-effective system that uses biological materials to remove heavy metals from water; however, it can be noted that an efficient and proven biosorbent for several heavy metal has not been found. Reed (Phragmites australis) has demonstrated to be a potential biosorbent to remove several heavy metals because it is commonly found as heavy metal accumulator in wetlands. This study is focused on mercury (Hg) removal by using reed as biosorbent. Batch experiments were conducted and the microstructure of the biosorbent was analyzed by scanning electron microscope. The Langmuir isotherm and Freundlich isotherm model was applied for the data obtained. The pseudo-first-order and pseudo-second-order models were used to test adsorption kinetics data to investigate the mechanism of biosorption. A comparison with the performance of various adsorbents reported in literature was made. The results contribute to understand the use of Phragmites australis as potential biomass for biosorbent technology since it removed mercury (Hg) effectively in high concentrations. This study supports a variety of researches to achieve clean water technologies, and biosorption has proved to be a useful alternative to the conventional systems for the removal of heavy metal ions from aqueous solution.

We report for the first time the capability of four-leaf clover (Marsilea quadrifolia), a wetland plant which grows rooted in soil, in efficiently treating sewage. The use of M. quadrifolia was made possible because of the special attributes of the SHEFROL® (SHEet Flow ROot Level) bioreactor in which it was employed. This bioreactor enables the use of free-floating aquatic plants as well as terrestrial and rooted-in-soil wetland plants by hydroponics. The plants are staked in narrow channels to enable them to support each other while sewage is made to flow rapidly as a sheet of wastewater at a level that covers only the plant roots (hence the name). It was seen that M. quadrifolia was able to treat sewage of strength varying in the chemical oxygen demand (COD) range of 600–1800 mg/L to the extent of > 80% at a hydraulic retention time (HRT) of just 4.5 h. There was a near total removal of biological oxygen demand and suspended solids while total Kjeldahl nitrogen, soluble phosphorous, and heavy metal zinc were also substantially removed. The macrophyte was equally effective when used indoors under artificial lighting, as well as when used outdoors.

The reduction of commonly used X-ray contrast iohexol (IOX) by the electrooxidation process is presented in this study. To begin with, the effect of anode material was examined, and different mixed metal oxide electrodes (MMOs) such as Ti/RuO₂, Ti/Pt, Ti/IrO₂-RuO₂, Ti/IrO₂-Ta₂O₅, Ti/Ta₂O₅-SnO₂-IrO₂, and Pt/SnO₂ were used. To assess experimental conditions at Ti/RuO₂ anode, provided the highest removal efficiency, the response surface method was applied and the key influencing parameter was the process time. The determined optimal conditions were triplicated with real wastewater samples, and the average degradation efficiency of IOX was found to be 99%. By-products of the IOX degradation on the Ti/RuO₂ anode have been identified using density functional theory and LC/MS-MS analysis. The results showed that IOX degradation opened with OH group detachment and resulted in the formation of a by-product with a molecular mass of 804 g mol⁻¹. Further degradation mechanism took place due to the breakup of C₄-C₁₀ and C₅-I₇ bonds with a by-product formed as 603 g mol⁻¹. Iodide atom replacement by OH groups caused the formation of a molecular fragment with 375 g mol⁻¹ molecular weight. The further disintegration of C₂-C₁₁ and C₆-N₁₆ σ- bonds led to the formation of molecular masses of 133, 126, and 119 g mol⁻¹, respectively.

The aim of this study was the isolation of bacterial strains which have the ability to decolorize synthetic dyes belonging to different chemical groups. The samples for bacterial isolation were collected from aqueous environments—two activated sludges and polluted local river. At the first stage of screening (performed on the solid media supplemented with two dyes—azo Evans blue or triphenylmethane brilliant green), 67 bacterial strains were isolated capable to decolorize the used dyes. In the further study, six dyes with different chemical structures were used: fluorone dyes (Bengal rose, erythrosine), triphenylmethane dyes (brilliant green, crystal violet), azo dyes (Evans blue, Congo red). Initial concentration of each of these chemicals in samples was 0.1 g/l. Obtained results showed that only 31 isolates were able to decolorize all six used dyes (with different efficiencies). Among them, 11 strains were isolated from the river (55% of isolates from this site) and 20 from activated sludges collected from two different treatment plants (15 from the first water treatment plant and 5 from the second which were 42 and 43% of isolated cultures respectively). The decolorizing microorganisms are mostly isolated from different industrial sewages (e.g., textile industry), but results of the study showed that water from polluted river as well as municipal wastewaters may be a precious source for isolation of bacterial strains with the wide spectrum and high decolorization potential. In general, there were no statistically significant differences between decolorization abilities of strains isolated from different sites. The group of dyes that was removed with the highest yield was triphenylmethanes (75.6%), followed by fluorones (70.0%) and azo group (60.9%). The analysis of decolorization efficiency of the individual dyes revealed the best removal results in case of triphenylmethane brilliant green (average removal 85.7%), followed by fluorone erythrosine (average removal 78.9%), triphenylmethane crystal violet (average removal 65.5%), azo Evans blue (average removal 64.4%), fluorone Bengal rose (average removal 61.0%), and azo Congo red (average removal 57.4%). Obtained results revealed that the dye susceptibility to decolorization depends on the characteristic chemical structure of given dye groups but more important is chemical structure of strictly given dye within the group.

The effect of biochar, derived from one-step microwave pyrolysis of sewage sludge (OMPSS), on the removal of industrial wastewater (eosin and safranine T) was investigated in this study. Meanwhile, the multiple-reuse potential of biochar as microwave receptor to raise the pyrolysis temperature was also tested during the pyrolysis process. The results showed that OMPSS prepared adsorbents had excellent adsorption performance, achieving the highest removal efficiencies of 97.3 and 95.9% for eosin and safranine T, respectively. Further analysis indicated that this was due to its appropriate porous structure and surface chemistry characteristics, where the SBET and pore volume of adsorbent AC-1 reached 459 m²/g and 0.23 cm³/g, respectively. The multiple reuses of biochar adsorbents after five times as microwave receptor was feasible, where the pyrolysis temperature could increase sharply from room temperature to 800 °C within 5 min. The mechanism analysis revealed that the limiting stage of adsorption was chemical sorption. This research provided an alternative way for the preparation of functional adsorbent and microwave receptor. Graphical abstract ᅟ

Limited data are available on ammonia (NH₃), nitrous oxide (N₂O), carbon dioxide (CO₂) and methane (CH₄) emissions from poultry housing in Mediterranean countries. The aim of the present study was to assess the NH₃, N₂O, CO₂ and CH₄ emission rates from commercial breeding hen and broiler houses under Mediterranean climate conditions. Research was conducted at one commercial breeding hen house and in two commercial broiler houses located in central Portugal. The environmental conditions, gas concentrations and ventilation rates were measured in the cold (8.0 ± 2.1 °C) and hot (20.7 ± 1.9 °C) season for the breeding hen house, whereas for the two broiler houses, measurements were made during one fattening cycle in the fall (17.3 ± 1.7 °C) season. Results showed that the annual average emission rates for breeding hen and broiler houses were 0.52 ± 0.27 and 0.06 ± 0.01 for NH₃, 0.030 ± 0.042 and 0.006 ± 0.001 for N₂O, 169.6 ± 56.2 and 58.0 ± 15.1 for CO₂ and 0.092 ± 0.131 and 0.0113 ± 0.0002 g day⁻¹ bird⁻¹ for CH₄, respectively. The N₂O emission rates observed in breeding hen houses may have been overestimated, being higher than previously reported for Mediterranean countries.

A series of experimental studies has been carried out using a novel, sustainable adsorbent to remove Tartrazine dye, namely, a steam activated carbon obtained from pecan nut shells. The dye also known as acid yellow 23 has been used in the food industry but is now classified as a carcinogen. The experimental equilibrium data has been used to test four equilibrium isotherm models and then the best fitting model was optimised to minimise the mass of adsorbent used to save costs in industrial applications using a two-stage batch adsorption system. The experimental contact time data has also been modelled and the best fit model has been used to optimise/minimise the contact time for a range of process conditions.

Increasing the retention of nutrients by agricultural soils is of great interest to minimize losses of nutrients by leaching and/or surface runoff. Soil amendments play a role in nutrient retention by increasing the surface area and/or other chemical processes. Biochar (BC) is high carbon-containing by-product of pyrolysis of carbon-rich feedstocks to produce bioenergy. Biosolid is a by-product of wastewater treatment plant. Use of these by-products as amendments to agricultural soils is beneficial to improve soil properties, soil quality, and nutrient retention and enhance carbon sequestration. In this study, the adsorption of NH₄-N, P, and K by a sandy soil (Quincy fine sand (QFS)) and a silty clay loam soil (Warden silty loam (WSL)) with BC (0, 22.4, and 44.8 mg ha⁻¹) and biosolid (0 and 22.4 mg ha⁻¹) amendments were investigated. Adsorption of NH₄-N by the QFS soil increased with BC application at lower NH₄-N concentrations in equilibrium solution. For the WSL soil, NH₄-N adsorption peaked at 22.4 mg ha⁻¹ BC rate. Biosolid application increased NH₄-N adsorption by the WSL soil while decreased that in the QFS soil. Adsorption of P was greater by the WSL soil as compared to that by the QFS soil. Biosolid amendment significantly increased P adsorption capacity in both soils, while BC amendment had no significant effects. BC and biosolid amendments decreased K adsorption capacity by the WSL soil but had no effects on that by the QFS soil. Ca release with increasing addition of K was greater by the WSL soil as compared to that by the QFS soil. In both the soils, Ca release was not influenced by BC amendment while it increased with addition of biosolid. The fit of adsorption data for NH₄-N, P, and K across all treatments and in two soils was better with the Freundlich model than that with the Langmuir model. The nutrients retained by BC or biosolid amended soils are easily released, therefore are readily available for the root uptake in cropped soils.

Roads and highways play an important function in the human-dominated Earth landscape and strongly affect the environment. Roadside ecosystems receive a number of pollutants, including deicing salt and inorganic nitrogen (N) from automobiles. We investigated how soil carbon (C) and N cycling were impacted by the application of salt (NaCl) and nitrate (NO₃⁻) to experimental plots in a field that is adjacent to Interstate 81, in Binghamton, NY. Experimental plots were constructed on two parallel transects; one was adjacent to the highway (0-m) and the other 50 m away from the highway (50-m). We hypothesized that the 0-m transect was exposed to roadway-derived pollutants over a long-term period of time, while the 50-m transect was exposed to fewer pollutants due to its distance from the road. Soils were collected in July and November 2011 and June and October 2012. Salt significantly decreased the rates of soil C mineralization and in situ soil respiration in both 0- and 50-m transects (p < 0.001), though it did not discernibly affect the rates of N mineralization or nitrification. Applications of NO₃⁻ had no significant impact on soil C or N mineralization. The effects of roadway pollutants were reflected in higher soil conductivities and pH at the 0-m transect. Under experimental salt treatment, C mineralization was reduced by 75% in the 50-m transect, compared to 20% reduction in the 0-m transect. We conclude that microbial communities near roads might have evolved to better withstand the impacts of roadway pollutants. Nevertheless, roads and vehicle traffic have strong impacts on the environment, and the application of road salt has important environmental consequences.

The correct name of the 2nd Author is Yusen Luo. The original article has been corrected.