Giant squid hydrolysate (GSH) elaborated from different batches from a fishing company was evaluated for cadmium removal. Fixed-bed column packed with iminodiacetic resin as adsorbent was used. GSH ...solution at different cadmium concentrations were fed in the fixed-bed column and breakthrough curves were evaluated. A high degree of metal removal from the solution was achieved and the saturation point (C
/C
≤ 0.8) was achieved more quickly at higher concentrations of cadmium. The maximum capacity of adsorption (q
) was obtained using the Thomas model, where 1137.4, 860.4, 557.4, and 203.1 mg g
were achieved using GSH with concentrations of 48.37, 20.97, 12.13, and 3.26 mg L
, respectively. Five cycles of desorption of the resin with HCl (1 M) backflow and regeneration with NaOH (0.5 M) were also evaluated, where no significant differences (
-value > 0.05) were observed between each cycle, with an average of 935.9 mg g
of q
. The
columns evaluated reached a total efficiency of 90% on average after the third column in GSH with a cadmium concentration of 20.97 mg L
. This kind of configuration should be considered the best alternative for cadmium removal from GSH. Additionally, the chemical composition of GSH, which was considered a quality parameter, was not affected by cadmium adsorption.
This work provides the basis for implementing a continuous treatment system using a bacterial consortium for wastewater containing a pesticide mixture of iprodione (IPR) and chlorpyrifos (CHL). Two ...bacterial strains (
C1 and
C4) isolated from the biomixture of a biopurification system were able to efficiently remove pesticides IPR and CHL at different concentrations (10 to 100 mg L
) from the liquid medium as individual strains and free consortium. The half-life time (
) for IPR and CHL was determined for individual strains and a free bacterial consortium. However, when the free bacterial consortium was used, a lower
was obtained, especially for CHL. Based on these results, an immobilized bacterial consortium was formulated with each bacterial strain encapsulated individually in alginate beads. Then, different inoculum concentrations (5, 10, and 15%
) of the immobilized consortium were evaluated in batch experiments for IPR and CHL removal. The inoculum concentration of 15%
demonstrated the highest pesticide removal. Using this inoculum concentration, the packed-bed bioreactor with an immobilized bacterial consortium was operated in continuous mode at different flow rates (30, 60, and 90 mL h
) at a pesticide concentration of 50 mg L
each. The performance in the bioreactor demonstrated that it is possible to efficiently remove a pesticide mixture of IPR and CHL in a continuous system. The metabolites 3,5-dichloroaniline (3,5-DCA) and 3,5,6-trichloro-2-pyridinol (TCP) were produced, and a slight accumulation of TCP was observed. The bioreactor was influenced by TCP accumulation but was able to recover performance quickly. Finally, after 60 days of operation, the removal efficiency was 96% for IPR and 82% for CHL. The findings of this study demonstrate that it is possible to remove IPR and CHL from pesticide-containing wastewater in a continuous system.
Botrytis cinerea and Penicillium expansum are phytopathogenic fungi that produce the deterioration of fruits. Thus, essential oil (EO) has emerged as a sustainable strategy to minimize the use of ...synthetic fungicides, but their volatility and scarce solubility restrict their application. This study proposes the EO of Oreganum vulgare and Thymus vulgaris-loaded solid lipid nanoparticles (SLN) based chitosan/PVA hydrogels to reduce the infestation of fungi phytopathogen. EO of O. vulgare and T. vulgaris-loaded SLN had a good homogeneity (0.21–0.35) and stability (−28.8 to −33.0 mV) with a mean size of 180.4–188.4 nm. The optimization of EO-loaded SLN showed that the encapsulation of 800 and 1200 μL L−1 of EO of O vulgare and T. vulgaris had the best particle size. EO-loaded SLN significantly reduced the mycelial growth and spore germination of both fungi pathogen. EO-loaded SLN into hydrogels showed appropriate physicochemical characteristics to apply under environmental conditions. Furthermore, rheological analyses evidenced that hydrogels had solid-like characteristics and elastic behavior. EO-loaded SLN-based hydrogels inhibited the spore germination in B. cinerea (80.9 %) and P. expansum (55.7 %). These results show that SLN and hydrogels are eco-friendly strategies for applying EO with antifungal activity.
•Solid lipid nanoparticles (SLN) were suitable nanocarriers for essential oil (EO)•EO-loaded SLN reduced mycelial growth and spore germination of fungi.•Hydrogel based on chitosan/PVA showed a good property to contain SLN.•EO-loaded SLN based hydrogel reduce spore germination of fungi.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Botrytis cinerea and Penicillium expansum produce deterioration in fruit quality, causing losses to the food industry. Thus, plant essential oils (EOs) have been proposed as a sustainable alternative ...for minimizing the application of synthetic fungicides due to their broad-spectrum antifungal properties. This study investigated the efficacy of five EOs in suppressing the growth of B. cinerea and P. expansum and their potential antifungal mechanisms. EOs of Mentha × piperita L., Origanum vulgare L., Thymus vulgaris L., Eucalyptus globules Labill., and Lavandula angustifolia Mill., were screened for both fungi. The results showed that the EO of T. vulgaris and O. vulgare were the most efficient in inhibiting the growth of B. cinerea and P. expansum. The concentration increase of all EO tested increased fungi growth inhibition. Exposure of fungi to EOs of T. vulgaris and O. vulgare increased the pH and the release of constituents absorbing 260 nm and soluble proteins, reflecting membrane permeability alterations. Fluorescence microscopic examination revealed that tested EOs produce structural alteration in cell wall component deposition, decreasing the hypha width. Moreover, propidium iodide and Calcein-AM stains evidenced the loss of membrane integrity and reduced cell viability of fungi treated with EOs. Fungi treated with EOs decreased the mitochondria activity and the respiratory process. Therefore, these EOs are effective antifungal agents against B. cinerea and P. expansum, which is attributed to changes in the cell wall structure, the breakdown of the cell membrane, and the alteration of the mitochondrial activity.
•Essential oils (EOs) have antifungal activity against B. cinérea and P. expansum.•EOs promote the release of fungal cell constituents of B. cinérea and P. expansum.•EO of O. vulgare and T. vulgaris altered fungal fluidity of cell membrane.•EO of O. vulgare and T. vulgaris altered the viability of spores and mycelia.•EO produce fungal physiological changes in mitochondria and cell wall of fungi.
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Dissolved Mn2+ in groundwater is dangerous for human health since it may act as a neurotoxin. To address this issue, sorption has emerged as an environmentally-friendly technology for Mn2+ removal. ...This study aimed to assess the effect of activation of Chilean natural zeolite, by modification of its compensating cations with NaCl, on its capacity for Mn2+ removal using batch and fixed-bed column studies. The natural and activated zeolites were characterized by SEM-EDS, TXRF, XRD, and N2 adsorption assays. The results of batch studies demonstrate that Na+ enhances the Mn2+ removal capacity of these zeolites from 4.55 to 5.9−1, with negligible changes in the pore structure. The experimental data fitted well with the pseudo-second-order kinetic and Langmuir adsorption models. Furthermore, MnOx(s) formed during the Mn2+ removal was identified on the surface of the zeolite by XRD and SEM-EDS analysis. The fixed-bed column studies were conducted at two bed heights: H1 (5 cm) and H2 (10 cm). The breakthrough curves adjusted to models of Thomas and Dose-response. The dose-response model adequately described both experimental data with an R2 > 0.90. The Mn2+ adsorption capacity of the system (qmdr) was 2.38 and 5.13 mg g−1, for H1 and H2, respectively. The regeneration of the activated zeolite was achieved using NaCl solution improving the efficiency of Mn2+ removal after reuse. This work highlights natural zeolite potential as an effective material for Mn2+ removal and as a viable technology to improve the water quality affected by geogenic contamination.
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•Zeolite is a promissory material for removing Mn(II) from aqueous solution.•Na+ modification enhances Mn (II) removal capacity, maintaining structure.•Manganese oxide formation was confirmed through XRD, SEM-EDS analysis.•Fixed-bed column studies allowed determinate the design parameters for scale-up.
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This study provides the basis for implementing a continuous treatment system for wastewater containing a pesticide mixture formed by atrazine, iprodione, and chlorpyrifos. Two fungal strains ...(Verticilium sp. H5 and Metacordyceps sp. H12) isolated from a biomixture of a biopurification system were able to remove different pesticide concentrations (10 to 50 mg L−1) efficiently from the liquid medium; however, the half-life of the pesticides was reduced and characterized by a T1/2 of 5.4 to 9.2 d for atrazine, 3.7 to 5.8 d for iprodione, and 2.6 to 2.9 d for chlorpyrifos using the fungal consortium. The immobilization of the fungal consortium in alginate bead was effective, with the highest pesticide removal observed using an inoculum concentration of 30% wv−1. The packed-bed reactor with the immobilized fungal consortium, which was operated in the continuous mode at different flow rates (30, 60, and 90 mL h−1), required approximately 10 d to achieve removal efficiency (atrazine: 59%; iprodione: 96%; chlorpyrifos: ~85%). The bioreactor was sensitive to flow rate fluctuations but was able to recover performance quickly. The pesticide metabolites hydroxyatrazine, 3,5-dichloroaniline, and 3,5,6-trichloro-2-pyridinol were produced, and a slight accumulation of 3,5,6-trichloro-2-pyridinol was observed. Nevertheless, reactor removal efficiency was maintained until the study ended (60 d).
Acid mine drainage, characterized by low pH and elevated heavy metal ion concentrations, causes severe harm to the environment. In this study, the feasibility of a new organic biomixture adsorbent ...for removing Fe3+, Zn2+, Cu2+ and Mn2+ metal ions from synthetic acid mine drainage was evaluated. This kinetic study showed fast metal ions adsorption within the first four to eight hours, and adsorption over 80% in the organic biomixture. The equilibrium adsorption isotherms resulted in a metal ion uptake greater than 84%, and the Freundlich model fitted well the data. The Freundlich affinity coefficient (Kf) ranged from 1.44 to 3.82 in the following order: Zn2+>Cu2+>Fe3+>Mn2+. Scanning electron microscope images revealed the heterogeneous structure of the biomixture, and energy-dispersive X-ray analysis after adsorption confirmed the ability of the biomixture to remove the metal ions. In the fixed-bed column, the Thomas model described (R2>0.95) the adsorption process of metal ions contained in the treated acid mine drainage well. The adsorption capacity (q0) of this system resulted in 164.2 mg g−1, 129.2 mg g−1, 26.0 mg g−1 and 15.3 mg g−1 of Fe3+, Zn2+, Cu2+ and Mn2+, respectively. This study confirmed the efficiency of an organic biomixture to adsorb metal ions and provide new and valuable information for the future design of low-cost treatments to reduce acid mine drainage pollution.
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•Organic biomixture efficiently removed metal ions from acid mine drainage.•The adsorption isotherms showed a metal ion uptake between 88 and 92%.•The maximum metal ion adsorption capacity ranged from 15.3 to 164.2 mg g-1.•The Thomas model described (R2 >0.95) the adsorption process of metal ions in the fixed-bed column well.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This study provides the basis for implementing a novel continuous treatment system for wastewater containing the pesticide atrazine (ATZ). Adsorption isotherms of ATZ from aqueous solution onto four ...biomixtures were determined. Based on the adsorption results, biomixture “B” (wheat straw, soil, and peat) was selected as the packing material for the fixed-bed column (FBC). The Response Surface Methodology (RSM) was used to optimize the combined effect of the inlet ATZ concentration (5–15 mg L−1), flow rate (10–50 mL h−1), and pH (4–8) of the FBC packed with biomixture “B” on ATZ removal. The dynamic behaviour of the FBC was investigated using the Thomas model under the optimal conditions obtained from the RSM. The results showed that pH was the determining factor in the adsorption process. Moreover, adsorption of ATZ decreased when the ATZ concentration and flow rate increased, especially at a basic pH. The optimum conditions for the adsorption of ATZ were a pH of 4.07, an influent ATZ concentration of 7.18 mg L−1, and a flow rate of 34.24 mL h−1 that resulted in the removal of 98.6% of the ATZ (corresponding to an adsorption capacity of 95.32 mg g−1). The Thomas model described the adsorption process to be well under optimal conditions (R2=0.9829). The findings of this study demonstrate that biomixture “B” could be successfully used as a low-cost adsorbent to remove ATZ from aqueous solution under continuous conditions.
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•Biomixture with wheat straw, soil, and peat selected for fixed-bed column packing.•Significant removal of atrazine from aqueous solution in acidic conditions.•Atrazine concentration, pH and flow rate optimized by Response Surface Methodology.•The highest bed capacity was 95.32 mg g−1 with flow rate of 34.24 mL h−1.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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