Search

Post‐consumer plastic film waste often carries organic and inorganic contaminants that challenge recycling processes and affect the quality of recycled products. An effective contaminant removal procedure through washing such single‐used plastic films (SUPFs) can address environmental and waste management concerns. This study compares the efficiency of different washing techniques in reducing SUPF contamination. To evaluate the efficacy of each washing technique, film samples collected from material recovery facilities are individually exposed to friction, ultrasonic‐assisted, and a combination of both washes. Thermal analysis indicates that the polymers' melting temperature, crystallization temperature, and crystallinity remain unaffected by the washing methods, demonstrating method aptness. Confocal laser scanning microscope images show that washing results in a cleaner sample surface. 91% ash reduction during the combined wash treatment indicates a high method efficiency compared to the individual friction and ultrasonic wash procedures. This is further validated by reducing characteristic contaminant IR bands (3600–3000, 1750–1600, and 1100–1000 cm−1). Elements of concern such as Cd, Cr, Hg, and Pb in SUPFs after each washing technique applied conform with regulations (<100 ppm) for packaging products. This research shows the novel ultrasonic washing reduces more contamination than friction with shorter wash times and no surfactants. [ABSTRACT FROM AUTHOR]

The aim of the study was to use regenerated activated carbon to adsorb phenol from a river. Coconut shell activated carbon was derived from used tap water filter cartridges. The activated carbon was carbonised and then activated with KOH at 200°C, under a nitrogen atmosphere. The resulting adsorbent was characterised on the basis of nitrogen adsorption by Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) analysis and point of zero charge (pH PZC). The study of periodic adsorption included kinetic and equilibrium modelling, determined the effect of solution pH on efficiency and the possibility of regeneration and reuse of the adsorbent. The efficiency of phenol removal from model water was evaluated, followed by the possibility of their adsorption from a polluted river in Silesia Province. Phenol adsorption followed pseudo-second-order kinetics. The adsorbents showed high adsorption abilities, as determined by the Langmuir isotherm model. The model fits the experimental data well. The concentration of phenol in the river was in the range of 0.45–0.77 mg∙dm– 3, which means that its value was at least five times higher than the standard values. The use of regenerated activated carbon from waste filter cartridges removed phenol from the river by 78% using optimal test parameters.

Eucalyptus wood vinegar (WV) is a versatile natural product employed in several areas such as for agriculture, zootechnics, and veterinary applications. However, the product may contain contaminants such as polycyclic aromatic hydrocarbons, methanol, metals, and so on in its raw form. Thus, refining is required to remove them. Only after reaching a high-purity grade can WV be applied as a basis for pharmaceuticals, antimicrobials, and additives for animal husbandry. This work aimed to assess the effect of refining on the contaminant content of a WV produced on an industrial scale and traded as agricultural input in the Brazilian market. WV was refined by sequential vacuum distillations and had its contaminant contents assessed before and after refining. The following chemical classes were investigated: metals and other elements, insecticides, fungicides, and herbicides (carbamates, organochlorines, organophosphates, pyrethroids, and others), mycotoxins, polychlorinated dioxins and furans, polycyclic aromatic hydrocarbons, and volatile organic compounds, encompassing more than 100 chemical species. Also, the WV physical–chemical properties before and after refining were determined. Gas chromatography and mass spectrometry (GC/MS) were employed to attain the WV's chemical profile. The main chemical components, such as phenolic compounds, furans, ketones, pyrans, etc., were annotated in the WV chemical profile. No traces of insecticides, fungicides, herbicides, heavy metals, mycotoxins, polychlorinated dioxins, or polychlorinated furans were found in raw WV or refined versions. However, several other undes/irable chemicals were determined in the raw product, such as PAHs and volatile organic compounds (acetaldehyde, acetone, ethylene glycol, and methanol). Nevertheless, all of them were effectively removed from the raw WV after the first or second sequential refining steps, resulting in a pure product. Therefore, only one refining step can be applied to raw WV to yield a high-quality product for pharmaceutical and animal husbandry applications. [ABSTRACT FROM AUTHOR]

The aim of the study was to use regenerated activated carbon to adsorb phenol from a river. Coconut shell activated carbon was derived from used tap water filter cartridges. The activated carbon was carbonised and then activated with KOH at 200°C, under a nitrogen atmosphere. The resulting adsorbent was characterised on the basis of nitrogen adsorption by Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) analysis and point of zero charge (pH PZC). The study of periodic adsorption included kinetic and equilibrium modelling, determined the effect of solution pH on efficiency and the possibility of regeneration and reuse of the adsorbent. The efficiency of phenol removal from model water was evaluated, followed by the possibility of their adsorption from a polluted river in Silesia Province. Phenol adsorption followed pseudo-second-order kinetics. The adsorbents showed high adsorption abilities, as determined by the Langmuir isotherm model. The model fits the experimental data well. The concentration of phenol in the river was in the range of 0.45-0.77 mg·dm-3, which means that its value was at least five times higher than the standard values. The use of regenerated activated carbon from waste filter cartridges removed phenol from the river by 78% using optimal test parameters. [ABSTRACT FROM AUTHOR]

The purpose of the paper was to create databases that would allow a proper assessment of the degree of marine pollution generated by shipyard industrial sector. The study was conducted over a period of three years, between 2015 and 2017. The parameters determined for the waters collected from the shipyard were within the maximum allowed limits according to the norms in force. However, values very close to the maximum allowable limit were observed in the case of groundwater for nickel, determined from the drilling located near the fuel depot in 2015 and chlorides determined from the drilling located near the galvanizing workshop, both in 2016 and in 2017. The analyzed parameters for the soil samples, collected from various sampling points and different depths, were below the value of the alert thresholds for less sensitive soils, according to Order 756/97. The databases created for this study can contribute as an incipient basis for the development of larger studies that include other industrial sectors as well as a longer evaluation period.

The quality of waters is disturbing day by day by various inorganic and organic pollutants. Among various strategies developed so far the technique of phytoremediation using aquatic plants is most preferable. Aquatic ecosystems are facing high level of stress and depletion due to the inputs of polluting materials. Nonetheless, there are certain species of aquatic macrophytes that have ability to cope with these stressful conditions even high concentration of various organic and inorganic pollutants present in water. These species are useful in polluted water treatment through phytoremediation or bioremediation technologies. Among the various aquatic plant species, Azolla, Eichhornia, Lemna, Potamogeton, Spirodela, Wolfia, and Wolfialla have been reported as phytoremediators and also they are highly efficient in reducing aquatic contamination through bioaccumulation of contaminants in their body tissues. Among the various aquatic species, water hyacinth (Eichhornia) is highly resistant and can tolerate the toxicity of heavy metals, phenols, formaldehydes, formic acids, acetic acids and oxalic acids even in their high concentrations. Likewise some other species of the family Lemnaceae are very efficient to reduce the percentage of biochemical oxygen demand (BOD), chemical oxygen demand (COD), as well as impact of HMs (heavy metals), and various ionic forms of nitrogen and phosphorus. Here in this review we are providing up-to-date information regarding the utilization of these aquatic plants for the bioremediation of contaminated waters. The review is primarily focused on the specific capabilities of aquatic plants and as an important tool in phytotechnologies in the management of contaminants in aquatic environment.

The semiconductor manufacturing industry produces large amounts of ammonia-contaminated wastewaters which require costly and energy-intensive treatments. This study demonstrates the application of a commercially available ceramic nanofiltration (NF) membrane for the control of organic and inorganic contaminants as well as ammonium retention in the treatment of semiconductor wastewater. Analysis of the hydrodynamic pore transport model based on the direct measurement of membrane thickness in the active layer indicated that the ceramic NF membrane has an average pore radius of ≈ 0.65 nm. Zeta potential measurements of the ceramic NF membrane showed that the membrane surface was negatively charged at neutral pH. The ammonium retention capacity of the ceramic NF membrane was evaluated using a single symmetric ammonium salt solution (1.8 mM NH 4 HCO 3 ; i.e., the average ammonium concentration in semiconductor wastewater) and combined salt solutions (mixtures of 1.8 mM NH 4 HCO 3 and either 2.0 mM of Na 2 SO 4 , CaSO 4 , or CaCl 2). The combined NH 4 HCO 3 and Na 2 SO 4 solution rendered a remarkably high ammonium retention rate of 88.7%, which was attributed to higher valency co-ions (SO 4 2-) in this solution with the same negative surface charge of the ceramic NF membrane. In contrast, the calcium ions (Ca2+) in different combined salt solutions containing CaSO 4 and CaCl 2 interfered with ammonium retention. We further employed the ceramic NF membrane to treat semiconductor wastewater samples taken from a full-scale semiconductor wastewater treatment plant and demonstrated that this proposed treatment method could effectively retain organic and inorganic contaminants with a low fouling propensity. Our results highlight the promising potential of ceramic NF membranes for the treatment of industrial wastewaters with diverse organic and inorganic contaminants. [Display omitted] [ABSTRACT FROM AUTHOR]

• Formation mechanisms of PFRs in BC are reviewed. • Catalytic role of BC-PFRs in environmental pollution remediation is evaluated. • BC-PFRs systems include redox, advanced oxidation, photocatalytic, and sonocatalytic system. • Future challenges of BC-PFRs in environmental pollution remediation are proposed. Biochar as an emerging carbonaceous material has exhibited a great potential in environmental application for its perfect adsorption ability. However, there are abundant persistent free radicals (PFRs) in biochar, so the direct and indirect PFRs-mediated removal of organic and inorganic contaminants by biochar was widely reported. In order to comprehend deeply the formation of PFRs in biochar and their interactions with contaminants, this paper reviews the formation mechanisms of PFRs in biochar and the PFRs-mediated environmental applications of biochar in recent years. Finally, future challenges in this field are also proposed. This review provides a more comprehensive understanding on the emerging applications of biochar from the viewpoint of the catalytic role of PFRs. [Display omitted] [ABSTRACT FROM AUTHOR]

The quality of waters is disturbing day by day by various inorganic and organic pollutants. Among various strategies developed so far the technique of phytoremediation using aquatic plants is most preferable. Aquatic ecosystems are facing high level of stress and depletion due to the inputs of polluting materials. Nonetheless, there are certain species of aquatic macrophytes that have ability to cope with these stressful conditions even high concentration of various organic and inorganic pollutants present in water. These species are useful in polluted water treatment through phytoremediation or bioremediation technologies. Among the various aquatic plant species, Azolla , Eichhornia, Lemna, Potamogeton, Spirodela, Wolfia, and Wolfialla have been reported as phytoremediators and also they are highly efficient in reducing aquatic contamination through bioaccumulation of contaminants in their body tissues. Among the various aquatic species, water hyacinth (Eichhornia) is highly resistant and can tolerate the toxicity of heavy metals, phenols, formaldehydes, formic acids, acetic acids and oxalic acids even in their high concentrations. Likewise some other species of the family Lemnaceae are very efficient to reduce the percentage of biochemical oxygen demand (BOD), chemical oxygen demand (COD), as well as impact of HMs (heavy metals), and various ionic forms of nitrogen and phosphorus. Here in this review we are providing up-to-date information regarding the utilization of these aquatic plants for the bioremediation of contaminated waters. The review is primarily focused on the specific capabilities of aquatic plants and as an important tool in phytotechnologies in the management of contaminants in aquatic environment. [ABSTRACT FROM AUTHOR]

The aim of the study was to evaluate the impact of potential pollution sources, mainly from the upstream anthropogenic sources and port-related activities. The in-vestigated area covered a wide range of anthropogenic im-pacts (e.g., industrial wastes, storm water runoff, acciden-tal oil spills, intentional discharges and shipping activities). The quality of water and Sediments was assessed us-ing Standard methods, as physical-chemical parameters, chemistry and biology (microbiology, ecotoxicology) aim-ing to figure the level of pollution and the effect of port-related activities. Seawater quality results agreed generally with environmental Standards. Though, in some samples the concentrations of sulphates (mg/1) and heavy metals (μg/1), as B, As and Se exceeded the recommended lim-its, without posing a serious environmental concern. Most of the surface sediment samples contain critical levels of hydrocarbons (C>12), (mg/kg), polycyclic aromatic hydrocarbons (ng/g) and polychlorobiphenyls (ng/g). For some heavy metals (mg/kg), exchangeable concentrations were found to be very close or above the regulations. The signifi-cance of this study is incontestable taking into account the lack of previous relevant historical data of this area. In this sense, it was possible to indicate, in general, good environmental conditions, despite the industrial and concentrated local port-related activities in the investigated area.

The continuous stream of polluted sediments, dredged from harbors and water bodies in order to maintain the navigation, is a common practice, but the fate of these sediments is an issue recognized worldwide. This pilot case study evaluated the application of phytoremediation as sustainable management strategy for the decontamination of polluted dredged marine sediments. The treatments were based on the use of different plant species ( Paspalum vaginatum Sw.; P. vaginatum Sw. + Spartium junceum L.; and P. vaginatum Sw. + Tamarix gallica L.) and organic matter (compost). The synergic action of plants and compost in removing both heavy metals (Cd, Ni, Zn, Pb, and Cu) and total petroleum hydrocarbons, and in recovering the nutritive and biological sediment properties were evaluated. In addition to the detection of total metal removal efficiency, the chemical distribution of metals in the sediment phases (exchangeable, manganese and iron oxides, organic matter, and residual minerals) was also measured in order to make a more realistic estimation of the phytoremediation efficiency for the sediment decontamination. Finally, a complete picture of the metal flux was obtained by investigating the metal mass-balance in the treated sediments. The results of metal content in the sediment phases showed that metal distribution was not uniform and each metal predominated in different fractions; the bioavailability of metals in the initial and treated sediments at 0–20 cm in the decreasing order was: Cd > Zn > Cu > Pb > Ni. The higher proportion of Ni and Pb in the residual phase can be the reason of the lower translocation of these metals in the plant tissues. On the other hand, Cd, Zn, and Cu were the metals most easily translocated in plant tissues, both aboveground and roots, confirming their higher bioavailability for the plants. The results of mass balance indicated that, at the end of the experimentation, a high content of metals were still found in the sediment. The greatest contribution in metal containment was attributed to a phytostabilization process at rhizosphere level followed by gravel and sand absorption. The capacity of rhizophere to precipitate heavy metals, could be considered as an alternative option for reducing the metal availability and, consequently, the toxicity in contaminated sediments. [ABSTRACT FROM AUTHOR]

• Water quality assessment of two rivers with critical and sustainable textile pollution. • High quantities of textile disperse dyes and metals, were detected in both samples. • Acute and chronic toxicities were detected in both water matrices. • Textile disperse dyes and metals are the possible contributors to the observed toxicity. Persistent organic and inorganic contaminants generated by industrial effluent wastes poses a threat to the maintenance of aquatic ecosystems and public health. The Khniss and Hamdoun rivers, located in the central-east of Tunisia, receive regularly domestic and textile wastewater load. The present study aimed to survey the water quality of these rivers using physicochemical, analytical and toxicological approaches. In the physicochemical analysis, the recorded levels of COD and TSS in both samples exceed the Tunisian standards. Using the analytical approach, several metals and some textile dyes were detected. Indeed, 17 metals were detected in both samples in varying concentrations, which do not exceed the Tunisian standards. The sources of metals pollution can be of natural and anthropogenic origin. Three textile disperse dyes were detected with high levels compared to other studies: the disperse orange 37 was detected in the Khniss river with a concentration of 6.438 μg/L and the disperse red 1 and the disperse yellow 3 were detected in the Hamdoun river with concentrations of 3.873 μg/L and 1895 μg/L, respectively. Textile activities were the major sources of disperse dyes. For both samples, acute and chronic ecotoxicity was observed in all the studied organisms, however, no genotoxic activity was detected. The presence of metals and textile disperse dyes could be associated with the ecotoxicological effects observed in the river waters, in particular due to the industrial activity, a fact that could deteriorate the ecosystem and therefore threaten the human health of the population living in the study areas. Combining chemical and biological approaches, allowed the detection of water ecotoxicity in testing organisms and the identification of possible contributors to the toxicity observed in these multi-stressed water reservoirs. [ABSTRACT FROM AUTHOR]

Zero valent iron (ZVI) has been extensively used for remediation of contaminated groundwater and wastewater. The removal of contaminants by alone ZVI is significantly limited by its intrinsic passive layer and influenced by the precipitation of iron (hydr)oxides on the surface of ZVI, which affects the further reaction of ZVI with contaminants. The premagnetization of ZVI and the addition of weak magnetic field (WMF) were proposed to resolve these problems. The application of a WMF is considered to be a promising and cutting-edge technology to increase the corrosion of ZVI, rejuvenate or improve the reactivity of ZVI, expand the range of target contaminants, and improve the removal efficiency of ZVI system. This study summarized the latest advances of WMF coupling with ZVI and magnetic ZVI derivative technologies for sequestration of (a) heavy metals, (b) arsenic, (c) selenium, (d) antimony, and degradation of (e) chlorinated organic compounds, (f) nitroaromatic compounds, (g) dyes, and (h) others. The remediation performance and reaction mechanisms were discussed and summarized. The results showed that WMF-ZVI and magnetic ZVI derivative technologies were the mainstream technology and had excellent remediation performance for the above contaminants. Concerning the future development and application of WMF-ZVI and magnetic ZVI derivative technologies, some suggestions are put forward and some conclusions are drawn. • Latest advances of WMF and magnetic ZVI derivative technology were summarized. • "Magnetic memory" of pre-magnetized ZVI were discussed and summarized. • Suggestions and conclusions were proposed for the future development of this cutting-edge technology. [ABSTRACT FROM AUTHOR]