Water, Air, & Soil Pollution最新文献

We investigated the mercury (Hg) concentration of the full range of needle age classes (NACs) in two conifers, nine NACs in Picea abies and fourteen in Abies pinsapo var. marocana, as well as three leaf age classes (LACs) in two broadleaved evergreen species, Trochodendron aralioides and Rhododendron catawbiense. Additionally, the Hg concentration of the wooden branch segments to which the NACs were attached in the two conifers was studied. Picea abies showed a continued Hg accumulation over all NACs, but with an age-dependent decline in the accumulation rate. In Abies pinsapo var. marocana, maximum needle concentrations of Hg were reached after eight years. The concentration remained constant for NACs 9–14, indicating that needles had become saturated with Hg. The Hg concentrations of the branch segments were much lower than those of the needles in the older NACs. Over the three LACs of Trochodendron aralioides and Rhododendron catawbiense there was a steady increase in concentration with a weak indication of a declining Hg uptake rate in older leaves. The average needle/leaf lifetime Hg uptake rate per year was only half that of broadleaved species across all NACs and LACs. We conclude that in conifers maintaining a larger number of NACs there is a decline of the Hg accumulation rate in older NACs. In future biogeochemical research (empirical and modelling) and biomonitoring studies, the age of sampled leaves needs to be considered to account for the age dependence of leaf Hg concentration and accumulation rate.

Marine debris is defined as any persistent, manufactured, or processed solid material that is intentionally or unintentionally disposed of or allowed to float into the marine environment. This debris can be of natural or artificial origin and includes a wide variety of materials, such as chemically treated wood. Fine woody debris (FWD), small particles with diameters ranging from 1 to 10 cm, can have natural and anthropogenic origin, which is often overlooked in coastal environments. In this study, we investigated FWD across multiple sites along the central Moroccan Atlantic coastline and identified 2068 FWD elements with an average density of 49.23 ± 38.07 items/m². Site 2, near a river, stood out for its notably greater density, in contrast to the lower densities observed at the other sites. Chemical characterization of the FWD surfaces revealed mechanical abrasions, along with traces of heavy metals (HMs) such as Cu and Ti, plastics (including PS, PP, PE, PA, and PVC), and pharmaceuticals (periciazine, dipyridamole, and canthaxanthin). These findings underscore the role of FWD as a reservoir and transporter of environmental contaminants such as microfibers, and HMs, which can leach into surrounding waters and be taken up by marine organisms. The presence of these contaminants highlights potential disruptions to marine biodiversity and ecological processes, including bioaccumulation and toxicity in aquatic food webs, habitat degradation, and altered nutrient cycling. Moreover, the global significance of these findings lies in their implications for biodiversity management and conservation strategies. Anthropogenic FWD not only represents a source of pollution but also a vector for spreading harmful substances, emphasizing the urgent need for effective management strategies. These include regular monitoring and targeted cleanup efforts to mitigate potential hazards, preserve ecosystem integrity, and enhance recreational experiences in dynamic coastal environments.

The impact of advanced oxidation processes (AOPs) integration with hydrodynamic cavitation (HC) along with energy-economics, has been studied towards the sustainable degradation of the organophosphate (OP) pesticide-contaminated agrochemical wastewater. Initially, the geometric interpretations of HC have been studied by hydrodynamic analysis towards selection of an optimal orifice device. The independent and integrated effects of AOPs were investigated for degradation. The optimal operational parameters for HC along with the degradation kinetics have been established. The reduction in total organic carbon (TOC) obtained by different approaches for 240 minutes of treatment time is reported. Treatment with HC alone resulted in 71% reduction, HC + H₂O₂ achieved 82%, HC + O₃ reached 79%, HC + H₂O₂ + O₃ resulted in 80% reduction. Among all combinations, based on energy-economics and kinetic-studies, the case of ozonation(O₃) given as pretreatment to HC has shown the highest degradation with 95% TOC reduction. In comparison to the simultaneous integration of O₃ with HC, the operational time required for TOC reduction of 90% was found to be 1.24 times lower with ozone pretreatment followed by HC operation, moreover the cost of operation drastically reduced by 14-fold. The byproduct analysis also shows that independent O₃ treatment for degradation, leads to the formation of secondary contaminants. However, the standalone HC process is found to be the most cost-effective, with 21-fold lesser operational costs as compared to the integrated processes but has a higher operational time. Therefore, the integrated process of O₃ pretreatment + HC was found to be a promising technology for OP degradation in terms of operational time and costs, while not generating any byproducts.

Large amounts of volatile organic compounds are released into the environment, and most have been shown to be harmful to humans. Dongting Lake is one of the important freshwater lakes in China, but there are few studies on the existence, distribution and risk assessment of volatile organic compounds in its water. This study investigated the emergence of volatile organic compounds (VOCs) within the surface water of Dongting Lake. A total of 15 different VOCs concentrations were measured in water samples from 21 sampling points. Fifteen kinds of VOCs have been detected; the one with the highest mean concentration is 1, 2-dichlorobenzene (1.039 μg/L), and the lowest is 1, 3, 5-trimethylbenzene (0.0034 μg/L). Of these, seven VOCs had a detection frequency of 100%. The total concentration of volatile organic compounds in the Nanzui waters was the highest among all the test sites. The Risk quotients (RQ) model has been adopted for evaluating the VOCs ecological risk, the RQ_total values of five sampling sites were higher than 1.0, indicating that the target compounds were at high risk or medium risk for related sensitive aquatic organisms. In addition, the carcinogenic risk of benzene is 2.45 × 10^–6, and the environmental exposure of benzene has a certain risk to human body but is within an acceptable range.The non-carcinogenic risks of toluene, benzene, ethylbenzene as well as xylene (BTEX) have been all less than 1.0, so it can be considered that there is no non-carcinogenic risk of BTEX to human body. Therefore, VOCs in Dongting Lake will not cause serious impact on human body, but it will pose a threat to aquatic organisms in some water areas.

Large volumes of polluted industrial wastewater discharges had made it imperative to continue on the development of adsorbent materials with improved adsorptive properties yet economically feasible. Agricultural waste such as date palm biomass offers an interesting solution as raw material due to its abundance and availability throughout the year. Biochar and hydrochar produced from date palm biomass were reported as a potent adsorbent to remove pollutants such as dyes from aqueous environment. However, very few studies had reported on the mechanism of dye removal by these types of adsorbents. Therefore, this study aimed to evaluate the methylene blue (MB) removal capacity of biochar (DPSB) and hydrochar (DPSH) produced from date palm seeds (DPS). This was followed by molecular dynamics studies (density functional theory, DFT) which was targeted to propose the geometry of the adsorbents as well as the interaction between MB and functional groups present on DPSB and DPSH. Finding from this molecular dynamics studies acted as the direct contribution of new knowledge for the interaction between DSP-based adsorbents and MB. DPSB and DPSH were produced from DPS samples that were collected from the Kingdom of Saudi Arabia's Hail region. FTIR analysis showed the presence of C = C, C = O, CO, and OH on both DPSB and DPSH while SEM micrographs reveal a highly porous structure with open pores and sharp edges in both samples. Thermogravimetric analysis (TGA) revealed a total weight loss of 20.79% for both samples. The maximum methylene blue (MB) removal of 85.6% (DPSB) and 89.4% (DPSH) was achieved at initial MB concentration of 10 mg L⁻¹, 2 g of adsorbent and equilibrium time of 45 min. Kinetic parameters (pseudo-first order and pseudo-second order interaction) were also used to evaluate the MB removal capacity. From the Density Functional Theory (DFT) analysis, all of the DPSH peaks exhibited an increase in intensity in the Band Gap of the hydrochar spectrum (-0.02102), indicating its resistant to chemicals and environmental degradation. To conclude, DPS were successfully demonstrated to be a useful alternative as raw material to produce biochar and hydrochar with good pollutant (MB) removal capacity. Nevertheless, more studies need to be carried out to ensure smooth transition of this type of adsorbent prior to any attempts for actual on-site application.

Tri-metallic SnAlFeO nanoparticles with surface functionalization were synthesized utilizing an easy and facial technique. For the analysis of the surface functionalization, shape, elemental ratio, crystal lattice, and functional group of these nanoparticles, a variety of analytical methods were employed. The nanoparticles displayed rice shape structure, according to SEM images. These rice-shaped nanoparticles were used to remove bromophenol blue (BPB) dye, a hazardous organic contaminant, from an aqueous solution. An incubator orbital shaker was utilized for shaking 0 to 120 min in pH tests in the range of pH 3 to 11.0. 50 to 200 mg of different adsorbent doses were used to investigate their effects. Many different adsorption isotherms (Langmuir, Freundlich, Temkin, etc.) and rate kinetics studies were used to investigate the adsorption of BPB dye using SnAlFeO nanoparticles. Pseudo-second-order kinetics model and Freundlich isotherms were found best fitted for the adsorption study of SnAlFeO nanoparticles. The exothermic phase includes mechanical forces according to the BPB dye adsorption. The n values of the model parameters were, respectively, n = 0.999, 0.967, and 0.944 at 298, 308, and 318 K. As a result, numerous horizontal molecule orientations were thought to be involved in the interactions between the active sites of BPB and SnAlFeO nanoparticles. Q_sat had values of 216.35, 9.241, and 1.642 mg/g at 298, 308, and 318 K, respectively. Q_sat results demonstrate that BPB molecules and SnAlFeO nanoparticles infrequently come into touch with one another as the temperature rises. Using an adsorption approach, this adsorbent demonstrated strong adsorption in industrial wastewater and has a lot of promise.

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The advanced peracetic acid (PAA) oxidation technology has a wide application prospect in the field of wastewater treatment for its high efficiency, environmental protection and wide application. In this work, cobalt tetraferrote (CoFe₂O₄) was used to activate PAA to degrade acid red B. The effects of CoFe₂O₄ catalyst dosage, PAA concentration, initial pH value and anion on the decolorization efficiency of acid red B were investigated by intermittent single factor experiments. The optimal reaction conditions for the degradation of 0.1 mM acid red B in the CoFe₂O₄/PAA system were as follows: catalyst dosage of 0.008 g, PAA concentration of 1 mM, and initial pH = 7. After 30 min of reaction, the degradation rate of acid red B reached was as high as 99.5%. The coexistence of CoFe₂O₄/PAA with low concentrations of anions and humic acid (HA) had negligible effects on the catalysis of acid red B, while the coexistence with higher concentrations of HCO₃⁻, H₂PO₄⁻ and HA inhibited the degradation behaviors. Quenching experiments confirmed that there were a large amount of R-O• and a small amount of •OH in the CoFe₂O₄/PAA system, and ¹O₂ played an important role in the degradation process. After 6 cycles, the catalytic performance of CoFe₂O₄ remained above 98.6%, showing stable catalytic performance, which were also confirmed by FTIR and XPS. This work provided a new way for effectively treating azo dye containing waste water.

Phosphorus (P) is an essential nutrient for all living organisms. However, excessive phosphorus input can damage aquatic ecosystems by overgrowth of algae, known as eutrophication. The present work studied the synergistic effect between reduced graphene oxide (rGO) and zero-valent iron nanoparticles (nZVI) on the phosphate removal ability from aqueous solution. Rice and wheat husk were used as agricultural waste for GO synthesis. rGO-nZVI composite was synthesized by the green method, using green tea extract. UV–Visible, XRD, SEM, EDS, FTIR, and Zeta potential identification techniques have confirmed the successful formation of the composite. The nZVIs were spherical and uniformly distributed on the rGO surface. A comparison of phosphate adsorption results with GO and rGO-nZVI adsorbents showed that the synthesized composite has improved the adsorption properties of GO. The effect of pH, contact time, adsorbent dosage, and initial adsorbate concentration have been intensively studied. The adsorption and kinetic mechanisms follow the Freundlich isotherm and pseudo-second-order kinetic models, respectively. The maximum adsorption obtained from the Langmuir was 16.99 mg/g. Phosphate has little reversibility due to its specific adsorption. rGO-nZVI composite is promising in water purification due to its ability to reduce phosphate in water.

Graphical Abstract

The study sampled wild Sesame from open field in South Africa. The samples were pretreated while the extracts were screened for phytochemical compositions and applied for water purification using standard procedures. The physicochemical properties of sampled raw and purified water (pH, total dissolved solids, salinity turbidity and conductivity) were analyzed in situ before and after treatment in the lab, respectively. The plant’s phytochemical extract from the leaves and stem was prepared using selected solvents (methanol, cold water and warm water). The results revealed the presence of phytochemicals including tannins, phenols, flavonoids, steroids, anthraquinone, terpenoids, saponins, and phlobatannins in both the stem and leaf of the wild Sesame plant. The study shows effective percentage reduction of E. coli and total bacteria with extracts of leaf (98.5, 100.0 and 97.2%), (98.8, 100.0 and 95.0%) and stem (94.0, 95.4 and 99.0%), (99.4, 98.6 and 98.4%) using methanol, cold and warm water, respectively, at 5ml of the phytochemical extracts. This study explores the use of wild Sesame phytochemicals for disinfecting river and stream water samples, highlighting the potential for greener and sustainable water treatment. The physicochemical parameters of the treated water were within tolerable limits, especially salinity and the total dissolved solids. Thus, the extract is presented as a potential solution for water purification, aligning with SDG goals 6 (clean water), 9, and 12 (green innovations). It fills the knowledge and product gap in water treatment, causing minimal harm, consistent with the African Union's sustainable development agenda and the African Council on Water's goal for clean water. This innovation meets the criteria for technology readiness levels 2 and 3, making it ready for further development.

While cobalt oxides (CoO, Co₃O₄) have attracted considerable interest in photoelectrocatalysis (PEC), supercapacitors, and lithium-ion batteries due to their inherent three-dimensional electronic structure. Herein, CoO nanowires were synthesized by one-step hydrothermal method, and then ZIF-67 was generated in situ on CoO nanowires by simple impregnation method. Finally, Ti/CoO@ZIF-67 composite electrode was synthesized. In order to find the PEC electrode with the best performance, we optimized the experimental system by adjusting the amount of organic ligand (0.01 mol, 0.015 mol, 0.02 mol, 0.025 mol). The PEC activity of Ti/CoO@ZIF-67 electrode was studied by electrochemical properties and degradation efficiency of Ti/CoO@ZIF-67 electrode for active brilliant blue (KN-R). The results show that the Ti/CoO@ZIF-67–0.02 electrode exhibits the largest specific surface area, the smallest charge radius, the fastest charge mass transfer rate and the highest PEC degradation efficiency for KN-R. The composite electrode with different amount of organic ligand showed higher degradation efficiency than the single component electrode. This is due to the staggered band structure of CoO and ZIF-67, which accelerates the effective separation of photogenerated electrons and holes on the surface of the electrode, and improves the mineralization effect of the composite electrode on organic polymer materials. This study provides an application strategy for the construction of composite heterojunction materials.