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Recyclable aminophenylboronic acid modified bacterial cellulose microspheres for tetracycline removal: Kinetic, equilibrium and adsorption performance studies for hoggery sewer
2022
Zhang, Gengrong | Li, Linhan | Zhou, Guoqing | Lin, Zhiyang | Wang, Jun | Wang, Gaoxue | Ling, Fei | Liu, Tianqiang
Significant concerns have been raised regarding to the pollution of antibiotics in recent years due to the abuse of antibiotics and their high detection rate in water. Herein, a novel super adsorbent, boronic acid-modified bacterial cellulose microspheres with a size of 415 μm in diameter was prepared through a facile water-in-oil emulsion method. The adsorbent was characterized by atomic force microscopy, scanning electron microscopy, and fourier transform infrared spectroscopy analyses to confirm its properties. The microspheres were applied as packing materials for the adsorption of tetracycline (TC) from an aqueous solution and hoggery sewer via the reversible covalent interaction between cis-diol groups in TC molecules and the boronic acid ligand. TC adsorption performance had been systemically investigated under various conditions, including the pH, temperature, TC concentration, contact time, and ionic strength. Results showed that the adsorption met pseudo-second-order, Elovich kinetic model and Sips, Redlich-Peterson isothermal models. And the adsorption process was spontaneous and endothermic, with the maximum TC adsorption capacity of 614.2 mg/g. After 18 adsorption-desorption cycles, the adsorption capacity remained as high as 84.5% compared with their original adsorption capacity. Compared with other reported adsorption materials, the microspheres had high adsorption capacity, a simple preparation process, and excellent recovery performance, demonstrating great potential in application on TC removal for water purification and providing new insights into the antibiotic's adsorption behavior of bacterial cellulose-based microspheres.
Mostrar más [+] Menos [-]Bio-based dispersants for fuel oil spill remediation based on the Hydrophilic-Lipophilic Deviation (HLD) concept and Box-Behnken design
2021
Nawavimarn, Parisarin | Rongsayamanont, Witchaya | Subsanguan, Tipsuda | Luepromchai, Ekawan
The high density and viscosity of fuel oil leads to its prolonged persistence in the environment and causes widespread contamination. Dispersants with a low environmental impact are necessary for fuel oil spill remediation. This study aimed to formulate bio-based dispersants by mixing anionic biosurfactant (lipopeptides from Bacillus subtilis GY19) with nonionic oleochemical surfactant (Dehydol LS7TH). The synergistic effect of the anionic-nonionic surfactant mixture produced a Winsor Type III microemulsion, which promoted petroleum mobilization. The hydrophilic-lipophilic deviation (HLD) equations for ionic and nonionic surfactant mixtures were compared, and it was found that the ionic equation was applicable for the calculation of lipopeptides and Dehydol LS7TH concentrations. The best formula contained 6.6% w/v lipopeptides and 11.9% w/v Dehydol LS7TH in seawater, and its dispersion effectiveness for bunker fuels A and C was 92% and 78%, respectively. The application of bio-based dispersants in water sources was optimized by Box-Behnken design. The efficiency of the bio-based dispersant was affected by the dispersant-to-oil ratios (DORs) but not by the water salinity. A suitable range of DORs for different oil contamination levels could be identified from the response surface plot. The dispersed fuel oil was further degraded by adding an oil-degrading bacterial consortium to the chemically enhanced water accommodated fractions (CEWAFs). After 7 days of incubation, the concentration of fuel oil was reduced from 3692 mg/L to 356 mg/L (88% removal efficiency). On the other hand, the abiotic control removed less than 40% fuel oil from the CEWAFs. This bio-based dispersant had an efficiency comparable to that of a commercial dispersant. The process of dispersant formulation and optimization could be applied to other surfactant mixtures.
Mostrar más [+] Menos [-]Spatial distribution, transport dynamics, and health risks of endosulfan at a contaminated site
2016
Fang, Yanyan | Nie, Zhiqiang | Die, Qingqi | Tian, Yajun | Liu, Feng | He, Jie | Huang, Qifei
We analyzed concentrations, distribution characteristics, and health risks of endosulfan (α and β isomers, and endosulfan sulfate) in soils (top soils and soil profiles) and air, at and around a typical endosulfan production site in Jiangsu, China. The air–soil surface exchange flux is calculated to investigate transport dynamics of endosulfan. Concentrations at the production site ranged from 0.01 to 114 mg/kg d.w. in soil and 4.81–289 ng/m3 in air, with very high concentrations occurring at the location of endosulfan emulsion workshop. In the surrounding area, endosulfan was detected in all samples, with concentrations ranging from 1.37–415 ng/g d.w. in soil and 0.89–10.4 ng/m3 in air. In the contaminated site, endosulfan concentrations fluctuated with depth in the upper soil layers, then decreased below 120 cm. Soil and air within a distance of 2.0 km appear to be affected by endosulfan originating from the site. Even the health risk at the location of the endosulfan emulsifiable solution workshop was over seven times the acceptable value, the risk to nearby adults and children was low.
Mostrar más [+] Menos [-]Effects of the technical ingredient clomazone and its two formulated products on aquatic macrophytes
2021
Stevanović, Marija | Brkić, Dragica | Tomić, Tanja | Mihajlović, Varja | Đorđević, Tijana | Gašić, Slavica
One active ingredient can be a component of different types of formulations of pesticides, while the toxicity of its formulations may vary depending on various constituents used in the mixture. The present study focuses on evaluating the effects of the active ingredient clomazone and its formulations (Rampa® EC and GAT Cenit 36 CS, both containing 360 g a.i./l of clomazone) on non-target aquatic macrophytes. The two formulation types differ in their active ingredient release and presumed environmental impact. In order to cover different ecological traits, two species of aquatic macrophytes – the floating monocot Lemna minor and the rooted dicot Myriophyllum aquaticum, were used as test models. The results of this study revealed differences in the sensitivity of tested plants to clomazone. Based on the most sensitive parameters, M. aquaticum proved to be more sensitive than L. minor to the technical ingredient and both formulations. The species sensitivity distribution (SSD) approach that was tried out in an attempt to create a higher tier step of risk assessment of clomazone for primary producers indicates that tests on rooted macrophytes can add value in risk assessment of plant protection products. The capsule formulation of clomazone was less toxic than the emulsion for L. minor, but more toxic for M. aquaticum. The most toxic for L. minor was the emulsifiable concentrate formulation Rampa® EC, followed by technical clomazone (EC₅₀ 33.3 and 54.0 mg a.i./l, respectively), while the aqueous capsule suspension formulation GAT Cenit 36 CS did not cause adverse effects. On the other hand, the most toxic for M. aquaticum was the formulation GAT Cenit 36 CS, followed by technical clomazone and the formulation Rampa® EC, demonstrating a greater effect of the capsule formulation.
Mostrar más [+] Menos [-]Eugenol mitigated acute lung but not spermatic toxicity of C60 fullerene emulsion in mice
2021
Pinheiro, Felipe Gomes | Moreira-Gomes, Maria Diana | Machado, Mariana Nascimento | Almeida, Tailane dos Santos | Barboza, Priscila da Penha Apolinário | Silva Oliveira, Luis Felipe | Ávila Cavalcante, Francisco Sales | Leal-Cardoso, José Henrique | Fortunato, Rodrigo Soares | Zin, Walter Araujo
C₆₀ fullerene (C₆₀) is a nano-pollutant that can damage the respiratory system. Eugenol exhibits significant anti-inflammatory and antioxidant properties. We aimed to investigate the time course of C₆₀ emulsion-induced pulmonary and spermatic harms, as well as the effect of eugenol on C₆₀ emulsion toxicity. The first group of mice (protocol 1) received intratracheally C₆₀ emulsion (1.0 mg/kg BW) or vehicle and were tested at 12, 24, 72 and 96 h (F groups) thereafter. The second group of mice (protocol 2) received intratracheally C₆₀ emulsion or vehicle, 1 h later were gavaged with eugenol (150 mg/kg) or vehicle, and experiments were done 24 h after instillation. Lung mechanics, morphology, redox markers, cytokines and epididymal spermatozoa were analyzed. Protocol 1: Tissue damping (G) and elastance (H) were significantly higher in F24 than in others groups, except for H in F72. Morphological and inflammatory parameters were worst at 24 h and subsequently declined until 96 h, whereas redox and spermatic parameters worsened over the whole period. Eugenol eliminated the increase in G, H, cellularity, and cytokines, attenuated oxidative stress induced by C60 exposure, but had no effect on sperm. Hence, exposure to C₆₀ emulsion deteriorated lung morphofunctional, redox and inflammatory characteristics and increased the risk of infertility. Furthermore, eugenol avoided those changes, but did not prevent sperm damage.
Mostrar más [+] Menos [-]Simultaneous photocatalytic reduction of hexavalent chromium and oxidation of p-cresol over AgO decorated on fibrous silica zirconia
2021
Aziz, F.F.A. | Jalil, A.A. | Hassan, N.S. | Fauzi, A.A. | Azami, M.S.
The co-existence of heavy metals and organic compounds including Cr(VI) and p-cresol (pC) in water environment becoming a challenge in the treatment processes. Herein, the synchronous photocatalytic reduction of Cr(VI) and oxidation of pC by silver oxide decorated on fibrous silica zirconia (AgO/FSZr) was reported. In this study, the catalysts were successfully developed using microemulsion and electrochemical techniques with various AgO loading (1, 5 and 10 wt%) and presented as 1, 5 and 10-AgO/FSZr. Catalytic activity was tested towards simultaneous photoredox of hexavalent chromium and p-cresol (Cr(VI)/pC) and was ranked as followed: 5-AgO/FSZr (96/78%) > 10-AgO/FSZr (87/61%) > 1-AgO/FSZr (47/24%) > FSZr (34/20%). The highest photocatalytic activity of 5-AgO/FSZr was established due to the strong interaction between FSZr and AgO and the lowest band gap energy, which resulted in less electron-hole recombination and further enhanced the photoredox activity. Cr(VI) ions act as a bridge between the positive charge of catalyst and cationic pC in pH 1 solution which can improve the photocatalytic reduction and oxidation of Cr(VI) and pC, respectively. The scavenger experiments further confirmed that the photogenerated electrons (e⁻) act as the main species for Cr(VI) to be reduced to Cr(III) while holes (h⁺) and hydroxyl radicals are domain for photooxidation of pC. The 5-AgO/FSZr was stable after 5 cycles of reaction, suggesting its potential for removal of Cr(VI) and pC simultaneously in the chemical industries.
Mostrar más [+] Menos [-]Structural and biological trait responses of diatom assemblages to organic chemicals in outdoor flow-through mesocosms
2014
Bayona, Yannick | Roucaute, Marc | Cailleaud, Kevin | Lagadic, Laurent | Bassères, Anne | Caquet, Thierry
The sensitivity of diatom taxonomy and trait-based endpoints to chemicals has been poorly used so far in Environmental Risk Assessment. In this study, diatom assemblages in outdoor flow-through mesocosms were exposed to thiram (35 and 170 μg/L), and a hydrocarbon emulsion (HE; 0.01, 0.4, 2 and 20 mg/L). The effects of exposure were assessed for 12 weeks, including 9 weeks post-treatment, using taxonomic structure and diversity, bioindication indices, biological traits, functional diversity indices, indicator classes and ecological guilds. For both chemicals, diversity increased after the treatment period, and responses of ecological traits were roughly identical with an abundance increase of motile taxa tolerant to organic pollution and decrease of low profile taxa. Bioindication indices were not affected. Traits provided a complementary approach to biomass measurements and taxonomic descriptors, leading to a more comprehensive overview of ecological changes due to organic chemicals, including short- and long-term effects on biofilm structure and functioning.
Mostrar más [+] Menos [-]Damping of surface waves due to crude oil/oil emulsion films on water
2019
Sergievskaya, Irina | Ermakov, Stanislav | Lazareva, Tatyana | Guo, Jie
In this paper results of laboratory studies of damping of gravity-capillary waves due to emulsified oil films (EOF) are presented and compared to crude oil films (COF). A laboratory method based on measuring the damping coefficient and the length of parametrically generated gravity-capillary waves is applied to a 50% EOF and to crude oil films. Measurements of wave damping were carried out in a range of surface wave lengths, corresponding to Bragg waves of X- to Ka-band radars. The obtained dependences of wave damping coefficient on EOF thickness have demonstrated the existence of a damping maximum at thicknesses of about 1–2 mm, and the maximum is approximately twice the one for COF, the damping maximum for EOF is located at larger film thicknesses than for COF. Theoretical calculations of wave damping have been performed and viscoelastic parameters of EOF have been estimated from comparison between theory and experiment.
Mostrar más [+] Menos [-]A new perspective of particle adsorption: Dispersed oil and granular materials interactions in simulated coastal environment
2017
Meng, Long | Bao, Mutai | Sun, Peiyan
This study, adsorption behaviors of dispersed oil in seawaters by granular materials were explored in simulation environment. We quantitatively demonstrated the dispersed oil adsorbed by granular materials were both dissolved petroleum hydrocarbons (DPHs) and oil droplets. Furthermore, DPHs were accounted for 42.5%, 63.4%, and 85.2% (35.5% was emulsion adsorption) in the adsorption of dispersed oil by coastal rocks, sediments, and bacterial strain particles respectively. Effects of controlling parameters, such as temperature, particle size and concentration on adsorption of petroleum hydrocarbons were described in detail. Most strikingly, adsorption concentration was followed a decreasing order of bacterial strain (0.5–2μm)>sediments (0.005–0.625mm)>coastal rocks (0.2–1cm). With particle concentration or temperature increased, adsorption concentration increased for coastal rocks particle but decreased for sediments particle. Besides, particle adsorption rate of petroleum hydrocarbons (n-alkanes and PAHs) was different among granular materials during 60 days.
Mostrar más [+] Menos [-]Phase and sedimentation behavior of oil (octane) dispersions in the presence of model mineral aggregates
2014
Gupta, Anju | Sender, Maximilian | Fields, Sarah | Bothun, Geoffrey D.
Adsorption of suspended particles to the interface of surfactant-dispersed oil droplets can alter emulsion phase and sedimentation behavior. This work examines the effects of model mineral aggregates (silica nanoparticle aggregates or SNAs) on the behavior of oil (octane)–water emulsions prepared using sodium bis(2-ethylhexyl) sulfosuccinate (DOSS). Experiments were conducted at different SNA hydrophobicities in deionized and synthetic seawater (SSW), and at 0.5mM and 2.5mM DOSS. SNAs were characterized by thermogravimetric analysis (TGA) and dynamic light scattering (DLS), and the emulsions were examined by optical and cryogenic scanning electron microscopy. In deionized water, oil-in-water emulsions were formed with DOSS and the SNAs did not adhere to the droplets or alter emulsion behavior. In SSW, water-in-oil emulsions were formed with DOSS and SNA–DOSS binding through cation bridging led to phase inversion to oil-in-water emulsions. Droplet oil-mineral aggregates (OMAs) were observed for hydrophilic SNAs, while hydrophobic SNAs yielded quickly sedimenting agglomerated OMAs.
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