Environmental Technology & Innovation最新文献

Discharging heavy metals into water bodies results in global environmental risks. Hexavalent chromium (Cr(VI)) is known as a harmful substance that poses substantial health hazards to humans. This study aimed to modify the pumice beads using a metal-organic composite synthesized by m-Phenylenediamine (mPD) and Iron (II) (FeCl₂·4H₂O) via a solvent-free method for photoreduction of the Cr(VI) to Cr(III) in wastewater. In the proposed method, iron (II) ions serve both as an electron generator and as a linker for the polymerization of mPD on the pumice surface in the high-temperature pyrolysis process. The optimum molar ratio of FeCl₂·4H₂O/mPD and the pyrolysis temperature were determined to be 1 and 700 °C. Moreover, the operative parameters such as pH, hole scavenger (formic acid) dosage, photocatalyst mass, Cr(VI) initial concentration, and reaction time were studied and the optimum condition was obtained as pH of 2.0, hole scavenger dosage of 20 mL L⁻¹, photocatalyst mass of 2 g, chromium concentration of 100 mg L⁻¹ and 13 min for irradiation time. The ability of the photocatalyst to reduce Cr(VI) at a concentration of 50 and 100 mg L⁻¹ under natural sunlight irradiation was also examined and a reduction efficacy of 100 % was achieved under optimum conditions within 40 and 60 min; respectively. Finally, the reusability test was conducted up to 10 cycles, and the results proved the durability and practicality of the prepared photocatalyst. The easy separation, short reaction time, and functioning under natural sunlight exhibited a promising application of the proposed photocatalyst for Cr(VI) reduction.

To improve the remediation effectiveness of biochar in heavy metal (HM) contaminated media, it is crucial to develop multifunctional biochar materials with enhanced adsorption performance for HMs. In this work, a versatile biochar fertilizer (MBF) with exceptionally high adsorption capacities and enhanced co-adsorption ability for multiple heavy metals was synthesized using corn straw as a precursor, and then employed as a remediation agent in HM-contaminated soil. The maximum adsorption capacity of MBF for Pb(II), Cd(II), Cu(II) and Zn(II) was 1666.74, 505.05, 304.88 and 250.00 mg/g, respectively, much higher than reported biochar adsorbents. Leaching experiment demonstrated that MBF showed strong co-adsorption ability for Pb (II), Cd (II), Cu (II) and Zn (II) with corresponding removal rate increased by 2.63, 2.3, 2.04 and 1.67 times than that of MgO-modified biochar. The removal efficiency of heavy metals by MBF was predominantly influenced by various factors, including the dissolution-precipitation of Mg-P precipitates, ion exchange with Mg²⁺, surface complexation, electrostatic attraction, and cation-π interaction. Noteworthy is that MBF not only significantly promoted the plant growth in both the normal and heavy metal-contaminated soil, but also inhibited the migration of the heavy metals into the seedlings. MBF has dual functions of remediating heavy metals and improving soil fertility, showing great potential in promoting the sustainable development of agricultural production.

Deep-sea environments are featured by low temperature and high hydrostatic pressure, which inhibits petroleum hydrocarbon metabolism by microorganisms. Herein, we developed novel bioremediating agents composed of different combinations of Pseudomonas zhaodongensis and dimethylsulfoniopropionate (DMSP) to promote oil degradation at deep-sea microcosm environment. First, through transcriptome sequencing, we revealed DMSP might provide hydrostatic pressure protection via secretion of potential piezolytes within the cell, which let bacteria healthy growth and thereby promoted oil biodegradation. Then, via oil measurement and high-throughput sequencing, we assessed effectiveness on using the studied agents and indigenous microorganism (i.e., natural remediation) to restore oil-contaminated muddy and sandy sediments at the microcosm, and demonstrated: 1) Oil degradation efficiency among different treatments using agents was 23.47 % – 41.02 % higher than that in natural remediation; 2) Each remediation plan defined specialized bacterial community. Marinobacter, Idiomarina, Sulfitobacter, Ferrimonas, Halodesulfovibrio, Paramaledivibacter and Pseudomonas were keystone oil-degrading taxa; 3) Overall, microbial community in sediment samples treated by bioremediation agents obtained better diversification of trophic interactions, structure stability and interference resistance; 4) Compared to natural remediation, pathways involving in oil component degradation and biogeochemical cycling exhibited varying degrees of up-regulation in agent-treated groups. Altogether, these results emphasize the crucial role of P. zhaodongensis and DMSP in enhancing bioremediation of oil-polluted sediments at typical deep-sea condition, and provide a novel idea for in-situ restoration of oil pollution at deep sea in future.

Antibiotics are extensively used as medicine for humans and also in livestock for growth promotion, disease prevention, and treatment. However, the pervasive usage of antibiotics has led to a critical global challenge raising issues regarding antibiotic-resistant bacteria and antibiotic-resistant genes. The presence of antibiotic-resistant bacteria and antibiotic-resistant genes poses a growing threat impacting the effectiveness of treatments for infectious diseases. Projections suggest that by 2050, there could be over 10 million deaths attributed to pathogens carrying antibiotic resistance genes. Consequently, there is a pressing need for methods that target the removal of residual antibiotics, eradication of antibiotic-resistant bacteria, and elimination of antibiotic-resistance genes specifically in wastewater treatment and livestock waste management before their release into the environment. This remediation approach aims to diminish the selective pressure on native bacteria in nature caused by antibiotics and mitigate the emergence of potential antibiotic-resistant strains. This review paper aims to outline the current status and significance of antibiotic control. Various contemporary strategies are employed to eliminate antibiotic residues, combat antibiotic-resistant bacteria, and counteract antibiotic-resistant genes. This review also evaluates the environmental impact assessment regarding antibiotic residues and antibiotic resistance genes on public health and the environment. The contribution of this review would provide insights into the multifaceted dimensions of antibiotic management and its implications for both human health and the ecosystem.

The enormous amount of colored effluent release from dying industries into fresh and marine reservoirs, causing ecotoxicity and serious health problems. Pertaining to this, the current research emphasis on the decolorization and degradation treatment of Indigo carmine (IC). The decolorization of IC with endophytic Microbacteium zeae K5, isolated from the root of the Salix purpurea plant was studied. In a minimal salt medium with shaking, full dye decolorization (400 mg/L) was achieved within a 24 h incubation period. During dye degradation, the activities of enzymes such as laccase (12.02 U/g), manganese peroxidase (4.23 U/g), and quinone dehydrogenase (0.09 U/g) were also observed. The biodegradation of IC into isatin sulfonic acid and isatin was confirmed by UV–VIS spectrophotometry and GC-MS analysis of dye samples extracted with ethyl acetate. Finally, phytotoxicity studies revealed that the IC degraded metabolites toxicity was lower than that of the parent dye compound. The current study demonstrated isolate M. zeae K5 has ability to efficiently break down IC, indicating its potential for future bioremediation uses.

To achieve the effective removal of low-concentration antibiotic pollutants present in seawater, floating photocatalytic spheres loaded with ytterbium-doped titania-loaded reduced graphene oxide (Yb-doped TiO₂/RGO) as active catalytic components were prepared and tested for the degradation of tetracycline (TC) in simulated seawater. Three solvothermal reduction processes were employed to promote TiO₂ crystallization in the Yb-doped TiO₂/RGO powder catalyst prepared via adsorption-layer nanoreactor synthesis, while simultaneously achieving the surface modification of the GO carrier in the active component. Doping with Yb and reduction reaction during solvothermal treatment converted a small amount of Ti⁴⁺ ions in TiO₂ into Ti³⁺ and introduced a low content of lattice oxygen vacancies, which extended the visible light response region of Yb-doped TiO₂/RGO. Under weak visible light excitation, the three Yb-doped TiO₂/RGO samples and their corresponding polyurethane (PU) sponge-filled photocatalytic spheres could effectively degrade TC in simulated seawater, with the highest degradation rates of 92 % (within 5 h) for the powder active component and 81 % (within 15 h) for the photocatalytic floating spheres. Use of ethanol and ethylene glycol as solvents led to the significant reduction in the hydrophilic groups of the Yb-doped TiO₂/RGO powder active component after heat treatment, effectively enhancing their TC adsorption performance in seawater. The eco-friendly PU sponge-filled photocatalytic spheres presented in this study exhibit a promising potential for effective removal of organic pollutants from seawater.

The co-steam gasification of biomass (straw) and Refuse-Derived Fuel (RDF) presents a promising pathway for sustainable waste management and renewable energy production, with significant implications for environmental protection. This study investigates the co-gasification of straw and RDF to optimize syngas production and minimize undesired by-products. The optimization of the S/M ratio and gasification temperature is crucial for efficient RDF gasification. The optimal S/M ratio and temperature balance syngas yield, quality (LHV), and process efficiency (carbon conversion efficiency and cold gas efficiency), while minimizing environmental hazards from solid residues. The carbon conversion efficiency of co-gasification of RDF increased by 12.7 % at the S/M 0 f 0.75 and gasification temperature of 800°C, a significant improvement compared to the efficiencies observed for the separate gasification of straw and RDF. Additionally, the gas yield and the cold gas efficiency were increased by 14.43 % and 26.42 % compared to the separate gasification processes, respectively. These results demonstrate the synergistic effects of co-gasifying straw and RDF, enhancing gasification performance and reducing tar formation. The study underscores the potential of co-steam gasification of straw and RDF as a technologically viable and environmentally friendly approach to waste-to-energy conversion, emphasizing the importance of operational optimization for achieving superior energy recovery, resource efficiency, and reduced environmental impact.

This study aims to investigate the differential inactivation responses of Escherichia coli and Staphylococcus aureus under rotary plasma jet conditions. Initially, we examined the antimicrobial effects of the rotary plasma jet on the two microorganisms under various operational parameters. Under optimal conditions (power: 1000 W, frequency: 30 kHz, flow rate: 45 NL/min, height: 4 cm, duration: 70 s), the treatment achieved an impressive 99.9 % inactivation of both bacterial strains. Notably, Staphylococcus aureus exhibited more excellent resistance when compared to Escherichia coli. Subsequently, we delved into changes in cell viability, cell granularity, and intracellular reactive oxygen species (ROS) levels before and after rotary spray plasma jet treatment to explore the differential inactivation mechanisms of the two microbial species. Cell viability assessments unveiled reduced viable cells and increased occurrence of dead cells and late-stage apoptotic cells for both microbial types, potentially attributed to augmented cell permeability and damage. Compared to Staphylococcus aureus, Escherichia coli exhibited notable enhancements in forward scatter (FSC) and side scatter (SSC) cell granularity detection signals yet displayed lower intracellular ROS levels. This discrepancy suggests that the primary cause of Escherichia coli inactivation may be cell envelope disruption. In contrast, Excessive intracellular ROS accumulation could be responsible for the inactivation of Staphylococcus aureus.

The performance of plastic carriers in a moving bed biofilm reactor used for water treatment is strongly determined by the carrier material and its shape. Only a few reports have described the effect of foaming on biofilm formation and nitrogen conversion by polypropylene (PP) carriers. Here, we investigated a PP foam carrier for its biofilm forming ability and the resulting biofilm’s ability to remove nitrogen compounds. The results revealed that foaming increased the amounts of denitrifying bacterial biofilms attached to PP by approximately 44 times, indicating that unevenness by foaming promoted biofilm formation. Biofilms were also formed using activated sludges from nitrification and denitrification of a wastewater treatment facility. Amplicon sequencing analysis of the biofilms revealed that the families Xanthomonadaceae and Comamonadaceae, including nitrifying bacteria, were enriched in nitrifying sludge-derived biofilms, whereas Dechloromonas sp. and family Pseudomonadaceae, including denitrifying bacteria, were enriched in denitrifying sludge-derived biofilms. Furthermore, nitrifying sludge-derived biofilms completely removed ammonia, and its removal ability was superior to that of the original sludge. Denitrification by denitrifying sludge-derived biofilms was promoted by the addition of fumaric acid. Both nitrifying and denitrifying sludge-derived biofilms could remove nitrogen compounds from 1.4 mM ammonia-containing synthetic wastewater. Finally, the effect of biomass addition on the carrier was investigated. The addition of composted seaweed waste to PP foam carriers enhanced the formation of denitrifying sludge-derived biofilms by approximately 2.2 times, and the denitrification reaction by biofilms was promoted. These results revealed that waste biomass can be used to further enhance PP foam carrier performance.

The improvement of mesophilic biomethanisation of recalcitrant sewage sludge derived from urban wastewater treatment through the application of a sonication pretreatment was evaluated in parallel in two pilot-scale anaerobic digesters (two biological replicates: reactors RA and RB). The valorisation process was monitored through a novel and holistic approach that related the biomethanisation yield, and its main batch operational parameters, with the abundance of archaeal and bacterial communities in the anaerobic inocula. Sonication allowed achieving a methane yield coefficient derived from sewage sludge of 240 ± 20 mL_STPCH₄/g VS (volatile solids) at the load range of 0.8–4.0 g VS/L in both reactors. The process was more stable in reactor B, with a wider range of loads being allowed (up to 5.29 g VS/L). Monitoring the presence of Archaea in the mixing liquor revealed a variation in their abundance throughout the process which was directly related to the availability of organic matter and pH. Advanced metagenomic analysis showed the phylogenetic and functional diversity of the complex microbiome involved. While Bacteria were widely distributed in 35 phyla, Archaea fitted in only two. Euryarchaeota was the majoritarian archaeal phylum (99.5 %) and its more abundant families are linked to methanogenic metabolism. Functional analysis revealed several relevant metabolic pathways that followed similar trends in both reactors. “Methane metabolism” clearly diminished at the end of the process in concordance with the exhaust of methane generation, while “ABC transporters” or “two-component systems”, involved in bacterial survival to changing environments, followed the opposite pattern. This integrated approach could help to increase the methanogenic valorisation of sewage sludge.