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Результаты 31-40 из 4,793
Enhanced treatment of organic matter in slaughter wastewater through live Bacillus velezensis strain using nano zinc oxide microsphere
2022
Deng, Jing | Jia, Mingxi | Zeng, Yu Qing | Li, Wen | He, JinTao | Ren, Jiali | Bai, Jie | Zhang, Lin | Li, Juan | Yang, Sheng
Slaughter wastewater is an important and wide range of environmental issues, and even threaten human health through meat production. A high efficiency and stability microsphere-immobilized Bacillus velezensis strain was designed to remove organic matter and inhibit the growth of harmful bacteria in process of slaughter wastewater. Bacillus velezensis was immobilized on the surface of sodium alginate (SA)/Polyvinyl alcohol (PVA)/Nano Zinc Oxide (Nano-ZnO) microsphere with the adhesion to bio-carrier through direct physical adsorption. Results indicated that SA/PVA/ZnO and SA/ZnO microspheres could inhibit E.coli growth with adding 0.15 g/L nano-ZnO and not affect Bacillus velezensis strain, and the removal the chemical oxygen demand (COD) rates of SA/PVA/ZnO microsphere immobilized cells are 16.99%, followed by SA/ZnO (13.69%) and free bacteria (7.61%) from 50% concentration slaughter wastewater within 24 h at 37 °C, pH 7.0, and 120 rpm, a significant difference was found between the microsphere and control group. Moreover, when the processing time reaches 36 h, COD degradation of SA/PVA/ZnO microsphere is obviously higher than other groups (SA/PVA/ZnO:SA/ZnO:control vs 18.535 : 15.446: 10.812). Similar results were obtained from 30% concentration slaughter wastewater. Moreover, protein degradation assay was detected, and there are no significant difference (SA/PVA/ZnO:SA/ZnO:control vs 35.4 : 34.4: 36.0). The design of this strategy could greatly enhance the degradation efficiency, inhibit the growth of other bacteria and no effect on the activity of protease in slaughter wastewater. These findings suggested that the nano-ZnO hydrogel immobilization Bacillus velezensis system wastewater treatment is a valuable alternative method for the remediation of pollutants from slaughter wastewater with a novel and eco-friendly with low-cost investment as an advantage.
Показать больше [+] Меньше [-]Effects of long-term exposure to the herbicide nicosulfuron on the bacterial community structure in a factory field
2022
Ma, Qingyun | Tan, Hao | Song, Jinlong | Li, Miaomiao | Wang, Zhiye | Parales, Rebecca E. | Li, Lin | Ruan, Zhiyong
This study aims to investigate the effects of long-term nicosulfuron residue on an herbicide factory ecosystem. High-throughput sequencing was used to investigate the environmental microbial community structure and interactions. The results showed that the main contributor to the differences in the microbial community structure was the sample type, followed by oxygen content, pH and nicosulfuron residue concentration. Regardless of the presence or absence of nicosulfuron, soil, sludge, and sewage were dominated by groups of Bacteroidetes, Actinobacteria, and Proteobacteria. Long-term exposure to nicosulfuron increased alpha diversity of bacteria and archaea but significantly decreased the abundance of Bacteroidetes and Acidobateria compared to soils without nicosulfuron residue. A total of 81 possible nicosulfuron-degrading bacterial genera, e.g., Rhodococcus, Chryseobacterium, Thermomonas, Stenotrophomonas, and Bacillus, were isolated from the nicosulfuron factory environmental samples through culturomics. The co-occurrence network analysis indicated that the keystone taxa were Rhodococcus, Stenotrophomonas, Nitrospira, Terrimonas, and Nitrosomonadaceae_MND1. The strong ecological relationship between microorganisms with the same network module was related to anaerobic respiration, the carbon and nitrogen cycle, and the degradation of environmental contaminants. Synthetic community (SynCom), which provides an effective top-down approach for the critical degradation strains obtained, enhanced the degradation efficiency of nicosulfuron. The results indicated that Rhodococcus sp. was the key genus in the environment of long-term nicosulfuron exposure.
Показать больше [+] Меньше [-]An iron-biochar composite from co-pyrolysis of incinerated sewage sludge ash and peanut shell for arsenic removal: Role of silica
2022
Wang, Qiming | Li, Jiang-shan | Poon, C. S. (Chi-sun)
Modification of biochar by low-cost iron sources has gained increasing attention to improve pollutants removal performance and reduce production costs compared to conventional chemical modifications. While such iron sources generally have complex compositions, their effects on properties of the iron-biochar composite are not well investigated. This study produced an iron-biochar (RBC) composite from co-pyrolysis of incinerated sewage sludge ash (ISSA) and peanut shell, and examined the role of silica with widespread existence in ISSA and other low-cost iron sources on properties of the iron-biochar composite relevant to As(III)/As(V) removal. Silica was found to react with iron during the pyrolysis process at 850 °C and formed iron silicon at the expense of producing zero valent iron and Fe₃O₄ which resulted in a poorer removal efficacy for As(III) and As(V) compared to the iron-biochar (FBC) made from pure Fe₂O₃ and peanut shell. Moreover, a high leaching of reactive silica from RBC was observed which affected the formation of corrosion products of ZVI and competed with arsenic for active adsorption sites. Despite this, RBC still exhibited a maximum adsorption capacity of 17.44 and 57.56 mg/g towards As(III) and As(V) respectively at pH 3.0. Overall, this study provides an interesting insight into upcycling ISSA into useful media for sorptive removal of arsenic from aqueous solutions.
Показать больше [+] Меньше [-]Yielding hydroxyl radicals in the Fenton-like reaction induced by manganese (II) oxidation determines Cd mobilization upon soil aeration in paddy soil systems
2022
Wang, Meng | Liu, Yongbing | Shi, Huading | Li, Shanshan | Chen, Shibao
As a redox-sensitive element, manganese (Mn) plays a critical role in Cd mobilization, especially in paddy soil. In an anoxic environment, the precipitation of Mn(II)-hydroxides specifically favors Cd retention, while draining the paddy fields results in substantial remobilization of Cd. However, how the change in Mn redox states during the periodical transit of anoxic to oxic systems affects Cd mobility remains unclear. In this study, we demonstrate that the radical effect generated during the oxidation of Mn(II)-hydroxides exerts a significant effect on the oxidative dissolution of Cd during the aeration of paddy soils. The extractable Cd concentration decreased rapidly during the reduction phases but increased upon oxidation, while Cd availability produced the opposite effect with soil pe + pH and the extractable Mn concentration. Inhibiting the oxidation of Mn(II)-containing phases by microbes suppressed the production of hydroxyl free radicals (•OH) and Cd mobilization in the drainage phase. Analysis of X-ray absorption spectroscopy and sequential extraction demonstrated that the transformation from the Mn phase of Mn(II) to Mn(III/IV) determines Cd solubility. Altogether, the oxidization of Mn(II)-hydroxides was associated with the generation of significant amounts of •OH. The dissolution of Mn(II)- incorporating phases lead to a net release of Cd into soils during soil aeration.
Показать больше [+] Меньше [-]Synthesized effects of medium-term exposure to seawater acidification and microplastics on the physiology and energy budget of the thick shell mussel Mytilus coruscus
2022
Sui, Yanming | Zhang, Tao | Yao, Xinyun | Yan, Ming | Yang, Liguo | Mohsen, Mohamed | Nguyen, Haidang | Zhang, Shengmao | Jiang, Hucheng | Lv, Linlan | Zheng, Liang
Ocean acidification (OA) and microplastics (MPs) contamination are two results of human excises. In regions like estuarine areas, OA and MPs exposure are happening at the same time. The current research investigated the synthesized effects of OA and MPs exposure for a medium-term duration on the physiology and energy budget of the thick shell mussel Mytilus coruscus. Mussels were treated by six combinations of three MPs levels (0, 10 and 1000 items L⁻¹) × two pH levels (7.3, 8.1) for 21 d. As a result, under pH 7.3, clearance rate (CR), food absorption efficiency (AE), respiration rate (RR), and scope for growth (SFG) significantly decreased, while the fecal organic dry weight ratio (E) significantly increased. 1000 items L⁻¹ MPs led to decrease of CR, E, SFG and increase of AE under pH 8.1. Interactive effects from combination of pH and MPs were found in terms of CR, AE, E and RR, but not for SFG of M. coruscus.
Показать больше [+] Меньше [-]Biochar composite derived from cellulase hydrolysis apple branch for quinolone antibiotics enhanced removal: Precursor pyrolysis performance, functional group introduction and adsorption mechanisms
2022
Zou, Mengyuan | Tian, Weijun | Chu, Meile | Gao, Huizi | Zhang, Dantong
In this study, magnetic biochar (MAB) and humic acid (HA)-coated magnetic biochar produced from apple branches without and after cellulase hydrolysis (HMAB and CHMAB, respectively) were prepared and tested as adsorbents of enrofloxacin (ENR) and moxifloxacin (MFX) in aqueous solution. Compared with MAB and HMAB, novel adsorbent CHMAB possessed a superior mesoporous structure, greater graphitization degree and abundant functional groups. When antibiotic solutions ranged from 2 to 20 mg L⁻¹, the theoretical maximum adsorption capacities of CHMAB for ENR and MFX were 48.3 and 61.5 mg g⁻¹ at 35 °C with adsorbent dosage of 0.4 g L⁻¹, respectively, while those of MAB and HMAB were 39.6 and 54.4 mg g⁻¹, and 44.7 and 59.0 mg g⁻¹, respectively. The pseudo-second-order kinetic model and Langmuir model presented a better fitting to the spontaneous and endothermic adsorption process. The maximum adsorption capacity of ENR and MFX onto CHMAB was achieved at initial pH values of 5 and 8, respectively. Additionally, the adsorption capacity of ENR and MFX decreased with increasing concentrations of K⁺ and Ca²⁺ (0.02–0.1 mol L⁻¹). Synergism between the pore-filling effect, π-π electron-donor-acceptor interactions, regular and negative charge-assisted H-bonding, surface complexation, electrostatic interactions and hydrophobic interactions may dominate the adsorption process. This study demonstrated that a novel magnetic biochar composite prepared through pyrolysis of agricultural waste lignocellulose hydrolyzed by cellulase in combination with HA coating was a promising adsorbent for eliminating quinolone antibiotics from aqueous media.
Показать больше [+] Меньше [-]Integrating 3D geological modeling and kinetic modeling to alleviate acid mine drainage through upstream mine waste classification
2022
Toubri, Youssef | Demers, Isabelle | Beier, Nicholas
Mine waste classification preceding mining constitutes a proactive solution to classify and segregate mine waste into geo-environmental domains based upon the magnitude of their environmental risks. However, upstream classification requires multi-disciplinary and integrated approaches. This study integrates geological modeling and kinetic modeling to inform upstream mine waste classification based on the pH generated from the main acid-generating and acid-neutralizing reactions once the mine solid waste is stored in oxidizing conditions. Geological models were used to depict the ante-mining spatial distribution of the main reactive minerals: pyrite, albite and calcite. Subsequently, the corresponding block models were created. The dimension of the elementary voxels for each block model was set at 40х40х40 m for this study. The kinetic modeling approach was performed using PHREEQC and VS2DRTI to consider unsaturated conditions. The kinetic modeling simulated a 1D column for each voxel. The column simulates the excavated state of the hosting rock involving kinetic reactions and unsaturated flow under highly oxidizing conditions. Subsequently, the resulting pH for different intervals of time was assigned to its respective voxel. The outcome consists of a spatio-temporal visualization of the pH defining ante-mining geo-environmental domains, thereby providing the opportunity for formulating proactive management measures regarding the hazardous geo-environmental domains.
Показать больше [+] Меньше [-]Biological effects of the antihypertensive losartan under different ocean acidification scenarios
2022
Pusceddu, F.H. | Guimarães, M.M. | Lopes, L.O. | Souza, L.S. | Cortez, F.S. | Pereira, C.D.S. | Choueri, R.B. | César, A.
Since the last decade, several studies have reported the presence and effects of pharmaceutical residues in the marine environment, especially those of the antihypertensive class, such as losartan. However, there is little knowledge about the physiological effects of losartan in marine invertebrates regarding its behavior under possible coastal ocean acidification scenarios. The objective of this study was to evaluate biological effects on marine organisms at different levels of the biological organization caused by the compound losartan in water and sediment under coastal ocean acidification scenarios. Water and sediment samples were collected at five sites around the Santos Submarine Sewage outfall (SSO) and two sites around the Guarujá Submarine Sewage Outfall (GSO). Losartan was found in concentrations ranging from <LOD to 7.63 ng/L in water and from <LOQ to 3.10 ng/g in sediments. Statistical analysis showed interactive effects pH and losartan on the toxicity results. The water toxicity test with Echinometra lucunter embryos/larvae showed LOECs 50–100 mg/L, with values decreasing as the pH decreased. In the sediment assays, LOEC value for sea urchin embryo-larval development was 1.0 μg/g for all tested pHs. Regarding the lysosomal membrane stability assays with adult bivalves, a LOEC of 3000 ng/L was found for Perna perna in water exposure (both at pH 8.0 and 7.6). Effects for Mytella guyanensis were observed at environmentally relevant concentrations in sediment (LOEC = 3 ng/g at pH 8.0 and 7.6). This study demonstrated that coastal ocean acidification by itself causes effects on marine invertebrates, but can also increase the negative effects of losartan in waterborne exposure. There is a need to deepen the studies on the ecotoxicity of pharmaceutical residues and acidification of the marine environment.
Показать больше [+] Меньше [-]Laccase production by Pleurotus ostreatus using cassava waste and its application in remediation of phenolic and polycyclic aromatic hydrocarbon-contaminated lignocellulosic biorefinery wastewater
2022
Kumar, Vaidyanathan Vinoth | Venkataraman, Swethaa | Kumar, P Senthil | George, Jenet | Rajendran, Devi Sri | Shaji, Anna | Lawrence, Nicole | Saikia, Kongkona | Rathankumar, Abiram Karanam
The treatment of contaminants from lignocellulosic biorefinery effluent has recently been identified as a unique challenge. This study focuses on removing phenolic contaminants and polycyclic aromatic hydrocarbons (PAHs) from lignocellulosic biorefinery wastewater (BRW) applying a laccase-assisted approach. Cassava waste was used as a substrate to produce the maximum yield of laccase enzyme (3.9 U/g) from Pleurotus ostreatus. Among the different inducers supplemented, CuSO₄ (0.5 mM) showed an eight-fold increase in enzyme production (30.8 U/g) after 240 h of incubation. The catalytic efficiency of laccase was observed as 128.7 ± 8.47 S⁻¹mM⁻¹ for syringaldazine oxidation at optimum pH 4.0 and 40 °C. Laccase activity was completely inhibited by lead (II) ion, mercury (II) ion, sodium dodecyl sulphate, sodium azide and 1,4 dithiothretiol and induced significantly by manganese (II) ion and rhamnolipid. After treating BRW with laccase, the concentrations of PAHs and phenolic contaminants of 1144 μg/L and 46160 μg/L were reduced to 96 μg/L and 16100 μg/L, respectively. The ability of laccase to effectively degrade PAHs in the presence of different phenolic compounds implies that phenolic contaminants may play a role in PAHs degradation. After 240 h, organic contaminants were removed from BRW in the following order: phenol >2,4-dinitrophenol > 2-methyl-4,6-dinitrophenol > 2,3,4,6-tetrachlorophenol > acenaphthene > fluorine > phenanthrene > fluoranthene > pyrene > anthracene > chrysene > naphthalene > benzo(a)anthracene > benzo(a)pyrene > benzo(b)fluoranthene > pentachlorophenol > indeno(1,2,3-cd)pyrene > benzo(j) fluoranthene > benzo[k]fluoranthène. The multiple contaminant remediation from the BRW by enzymatic method, clearly suggests that the laccase can be used as a bioremediation tool for the treatment of wastewater from various industries.
Показать больше [+] Меньше [-]Bioimaging revealed contrasting organelle-specific transport of copper and zinc and implication for toxicity
2022
Yuan, Liuliang | Wang, Wen-Xiong
Zn and Cu are two of the essential trace elements and it is important to understand the regulation of their distribution on cellular functions. Herein, we for the first time investigated the subcellular fate and behavior of Zn and Cu in zebrafish cells through bioimaging, and demonstrated the completely different behaviors of Zn and Cu. The distribution of Zn²⁺ was concentration-dependent, and Zn²⁺ at low concentration was predominantly located in the lysosomes (76.5%). A further increase of cellular Zn²⁺ resulted in a spillover and more diffusive distribution, with partitioning to mitochondria and other regions. In contrast, the subcellular distribution of Cu⁺ was time-dependent. Upon entering the cells, Cu²⁺ was reduced to Cu⁺, which was first concentrated in the mitochondria (71.4%) followed by transportation to lysosomes (58.6%), and finally removal from the cell. With such differential transportation, Cu²⁺ instead of Zn²⁺ had a negative effect on the mitochondrial membrane potential and glutathione. Correspondingly, the pH of lysosomes was more sensitive to Zn²⁺ exposure and decreased with increasing internalized Zn²⁺, whereas it increased upon Cu²⁺ exposure. The responses of cellular pH showed an opposite pattern from the lysosomal pH. Lysosome was the most critical organelle in response to incoming Zn²⁺ by increasing its number and size, whereas Cu²⁺ reduced the lysosome size. Our study showed that Zn²⁺ and Cu²⁺ had completely different cellular handlings and fates with important implications for understanding of their toxicity.
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