Clean-soil Air Water最新文献

Petroleum-contaminated soil (PCS) is urgently to be remediated due to its risk to ecological environment and human health. In this study, a Fenton oxidation–pyrolysis strategy was employed to accomplish effective petroleum removal and PCS remediation. The highest total petroleum hydrocarbon removal efficiency could achieve 99.6% after 2 h Fenton oxidation, with H₂O₂/Fe²⁺, 6:1, and pH 3, followed by pyrolysis at 370°C. The organic compositions of the soil after Fenton oxidation, the kinetics and process of the pyrolysis, morphologies and structures of the treated soil, as well as energy consumption and cost savings were comprehensively researched and analyzed. Through the Fenton oxidation–pyrolysis treatment, the macromolecules were effectively degraded and the contents of asphaltenes and resins were significantly reduced in the soil. Graphitized carbon was dominatingly existed after the pyrolysis. A 1.5 order reaction model was proposed to reasonably describe the pyrolysis remediation process of PCS. The Fenton oxidation–pyrolysis treatment can reduce energy consumption and cost compared with pyrolysis alone. This work not only offered an alternative approach of PCS remediation, but also provided theoretical guidance for practical soil remediation.

Pig production contributes significantly to the high environmental footprint of the livestock sector. Therefore, in this framework, a transition toward more sustainable production is essential. Local natural livestock resources, such as Mexican Creole Hairless Pigs, provide a good opportunity to achieve sustainable pig production. In the present study, a first approximation to compare the carbon emissions of Mexican Creole Hairless Pig manure from Commercial Pig manure is presented. Under the same feeding and housing conditions, the specific methane emissions of both Mexican Creole Hairless Pigs and Commercial Pigs manure were determined experimentally at room temperature. In addition, specific methane production kinetics was modeled using the Gompertz equation to estimate the specific methane production rate. The methane emission factors for Mexican Creole Hairless Pig manure (0.33 ± 0.02 kg[CO₂-eq]/LU per day) were half those of Commercial Pig manure (0.7 ± 0.04 kg[CO₂-eq]/LU per day), and biochemical manure analysis suggested that Mexican Creole Hairless Pigs had better digestibility of the diet. In general, due to physiological factors such as food intake rate and gut microbiota development, which could influence the fat and fiber digestibility of Creole genotypes, pig genotype should be included as an additional factor to estimate greenhouse gas emissions from pig manure. The production of Mexican Creole Hairless Pigs in an extensive local system is therefore an attractive option for developing new sustainable markets.

Antibiotic residues in water represent an urgent environmental challenge. To efficiently remove these residues, a low-carbon integrated biochar synthesis method was proposed, and an optimized typha biochar (TBI_K) was prepared. Compared with the biochar prepared by a conventional two-step carbonization and activation method (TBT_K), the TBI_K preparation process reduced energy consumption by 43849.58 J and cut carbon dioxide emissions by 32.80%. TBI_K exhibited a large surface area of 1252.40 m²/g and rapidly achieved an equilibrium removal efficiency of 99.95% within 20 min for simulated antibiotics wastewater. Furthermore, TBI_K possessed more number of functional groups than TBT_K, especially O-H and C-S groups. The adsorption stability and tolerance of TBI_K in solutions with different ionic strengths and coexisting anions were examined. Characterization techniques such as scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) as well as Brunauer, Emmett and Teller (BET) analyses were employed to elucidate the morphology and adsorption mechanism of the adsorbent. The microporous structure and abundance of functional groups are key to the excellent adsorption capabilities of TBI_K. Thus, this integrated method for biochar production, optimized for treating antibiotic wastewater, holds significant potential for future applications.

Tannery effluent waste comprises various potentially toxic metals, including chromium (Cr) with varying acute or chronic toxicity. Cr(VI) is known to be a category-A carcinogen. Reduction of toxic Cr(VI) to Cr(III), which has lesser bioavailability, is one of the mechanisms used by many microbes to withstand Cr(VI) toxicity in the contaminated effluents. Oxidoreductase (OXRs) reduces toxic Cr(VI) to Cr(III); hence a thorough understanding of the OXRs is important for developing a suitable strategy to minimize Cr(VI) toxicity. Therefore, the OXR-encoding genes were sequenced using metagenomic DNA shotgun sequencing from the tannery effluent-contaminated soil. Six OXR-encoding genes were expressed in Escherichia coli, and OXR activity was confirmed by in situ quantitative assays. The six proteins were subjected to phylogenetic and evolutionary analysis. Further, detailed structural analysis of the two OXRs, namely, OXR3 and OXR8 with lowest and highest activity respectively, were investigated in silico for structural characteristics. The results revealed that both the proteins were soluble FMN-linked oxidoreductases. Eight conserved active site residues (Pro24, Thr26, Ala59, Tyr139, His178, Tyr180, His219, Tyr221, Arg269, and Lys360) in the enzyme OXR3 were predicted. Similarly, nine conserved active site residues (Pro20, Thr22, Ala55, Glu97, His191, Tyr193, Arg241, Cys334, and Arg335) were predicted in OXR8. The tertiary structure of OXR8 was an aldolase TIM barrel structure, like Thermus scotoductus chromate reductase. Docking with FMN revealed the involvement of all the nine predicted active site residues in FMN binding with Pro20, Thr22, and Cys334 as the most important ones.

Industrial water pollution originating from various industries like textile, dairy, oil, and petrochemical industries, etc. is a huge concern globally and has led to devastating effects on the environment due to the release of refractory emerging contaminants (ECs). These ECs of concern have attracted wide devotion from the scientific community due to their recalcitrant nature and disastrous effects on plants, aquatic life forms, and humans. In this regard, conventional wastewater treatment technologies such as coagulation, flocculation, membrane technologies, electrocoagulation, and other biological technologies like sequencing batch reactor, anaerobic up-flow sludge blanket reactor, etc., are inefficient in removing ECs from the industrial effluent, while conventional advanced oxidation processes incur high cost due to the extensive requirement of energy for the degradation of ECs. To overcome this issue, microbial electrochemical technologies (METs) can be employed. For instance, METs have shown promising results in the degradation of various ECs, such as microbial fuel cells, which have shown nearly 92% to 98% removal of sulfamethoxazole with simultaneous power recovery. Alizarin yellow R, nitrobenzene, and Congo red were degraded by microbial electrolysis cells with removal efficiency in the range of 88% to 98%, demonstrating their superiority in the elimination of trace contaminants. Similarly, almost 100% mineralization of pyraclostrobin was noticed for the bio-electro-Fenton process, showing the elevated potential of these neoteric technologies for the remediation of recalcitrant pollutants. Thus, the current review article aims to critically analyze the intervention of METs for the elimination of ECs from industrial wastewater.

During the period 2019–2020, size-segregated aerosol samples containing elemental and organic carbon (EC and OC) were investigated. These samples were collected weekly using an eight-stage cascade impactor from an urban site located at Aksaray University, Aksaray. The quantification of EC and OC was carried out through a thermal-optical transmission device. The results revealed consistent size distribution attributes of EC and OC between winter and summer. Although EC accounted for an insignificant percentage (4.4%) of particulate matter (PM) in the PM_9.0–10.0 fraction during winter, a more substantial portion of OC in the same fraction (13.4%) comprised EC. Seasonal variations were distinct for EC but not significant for OC. Strong correlations between OC and EC were observed in coarse particle fractions, indicating a common source, with weaker correlations in fine particles. The highest OC/EC ratio was in the PM_0.43–0.65 fraction, followed by PM_2.1–3.3. The ratio of OC to EC in fine PM exceeded the threshold of 15 consistently. The observation indicates that as particle size increases, there is a noticeable decline in the OC to EC ratios. Secondary organic aerosols (SOA) accounted for 60.8% (winter) and 89.8% (summer) of OC values, emphasizing the substantial impact of SOA on Aksaray's atmosphere. Both seasons exhibited a multimodal distribution of ambient OC. In winter, the EC distribution was dominated by fine particles, with a bimodal pattern (PM_1.1–2.1 and PM_0.43–0.65 peaks). Common pollutant sources, including traffic emissions, road dust, biogenic emissions, and coal combustion, were identified for both seasons in coarse and fine particle fractions. These findings underscore the importance of emission control strategies targeting fine PM in Aksaray.