Effect of Chitosan-Riboflavin Bioconjugate on Green Mold Caused by Penicillium digitatum in Lemon Fruit.

Penicillium digitatum is the causal agent of green mold, a primary postharvest disease of citrus fruits. This study evaluated the efficacy of a novel photoactive chitosan-riboflavin bioconjugate (CH-RF) to control green mold in vitro and in lemon fruit. The results showed total inhibition of P. digitatum growth on APDA supplemented with CH-RF at 0.5% (w/v) and a significant reduction of 84.8% at 0.25% (w/v). Lemons treated with CH-RF and kept under controlled conditions (20 °C and 90-95% relative humidity) exhibited a noteworthy reduction in green mold incidence four days post-inoculation. Notably, these effects persisted, with all treatments remaining significantly distinct from the control group until day 14. Furthermore, CH-RF showed high control of green mold in lemons after 20 days of cold storage (5 ± 1 °C). The disease incidence five days after cold storage indicated significant differences from the values observed in the control. Most CH-RF treatments showed enhanced control of green mold when riboflavin was activated by white-light exposure. These findings suggest that this novel fungicide could be a viable alternative to conventional synthetic fungicides, allowing more sustainable management of lemon fruit diseases.

Effective Cd2+ removal from water using novel micro-mesoporous activated carbons obtained from tobacco: CCD approach, optimization, kinetic, and isotherm studies.

PURPOSE: This research aimed to develop activated carbons from tobacco by double (thermal-physical) and triple activations (thermal-chemical-physical) for high-efficiency removal of Cd2+. METHODS: The adsorbents were characterized by their chemical composition, point of zero charge (pHPZC), SEM, FT-IR, BET, and BJH. The subsequent adsorption studies were conducted: optimal conditions (CCD on adsorbent dose versus pH of Cd2+ solution), kinetics, equilibrium, thermodynamics, and desorption studies. RESULTS: The activated carbons have irregular and heterogeneous morphology, surface functional groups COO-, C-O, C-O-C, C=O and O-H, pHPZC of 11.11 and 10.86, and enhanced SSA (especially for CT NaOH + CO2 = 103.40 g m-2). The optimal conditions for Cd2+ adsorption occur using 4.0 g L-1, pH from 3.0 to 7.0, with most of the Cd2+ adsorbed in the first 10-20 min. The goodness of the fit found for pseudo-first order, pseudo-second order, intraparticle diffusion, Langmuir, Freundlich, Dubinin-Radushkevich, Sips, and Temkin suggest the occurrence of Cd2+ chemisorption and physisorption in mono and multilayers. The values of ∆G° < 0 kJ mol-1 indicate that the observed phenomena are energetically favorable and spontaneous; the values of ∆H° < 0 and the effective desorption rates (58.52% and 44.64%) suggest that the adsorption of Cd2+ is ruled mainly (but not only) by physical interactions. CONCLUSION: Our excellent results on Cd2+ removal allow us to state that tobacco use as a raw material for adsorbent development is a renewable and eco-friendly technique, allowing the production of highly effective activated carbons and providing an adequate destination for this waste. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40201-021-00740-8.

Eco-friendly, renewable Crambe abyssinica Hochst-based adsorbents remove high quantities of Zn2+ in water.

Although not considered poisonous and with natural occurrence, Zn contamination is mainly related to anthropic actions. This research aim was to develop, from crambe wastes, adsorbents with high adsorption capacity of Zn2+. The crambe biomass was modified with H2O2, H2SO4 and NaOH 0.1 mol L-1, resulting in four crambe-based adsorbents: C. in natura (unmodified), C. H2O2, C. H2SO4 and C. NaOH. These were studied by determination of their chemical components, SEM, FTIR, pHPZC, thermal stability (by TG/DTG curves), SSA, pore volume and pore diameter (by BET and BJH). Adsorption studies were also carried out to evaluate its Zn removal capacity. Evaluations were taken on adsorbent dose and the influence of the pH, as well as studies on adsorption kinetics and equilibrium. These results were evaluated by pseudo-first order, pseudo-second order, Elovich, intraparticle diffusion, Langmuir, Freundlich, Dubinin-Radushkevich and Sips (linear and nonlinear models). Results show that the crambe-based adsorbents may have functional groups such as hydroxyls, amides, carbonyls and carboxylates, which may be responsible for the Zn2+adsorption. The materials have heterogeneous structure, allowing the occurrence of mono and multilayer adsorption of Zn. The finest results point out the occurrence of mono and multilayer of Zn2+ (evidenced by Sips-nonlinear model), with an increase in Qsat of 72% (C. H2O2), 22% (C. H2SO4) and 80% (C. NaOH). The developed crambe adsorbents have low cost of production (since the raw material is until now a solid waste) and have high removal ratio of Zn2+ from waters, being a promising technology.

Determination of CHLORPYRIFOS by GC/ECD in water and its sorption mechanism study in a RHODIC FERRALSOL.

The validation of chromatographic methods is a costly process, however necessary, especially with regard to the validation of methods that accurately determine concentrations of pesticides in different environmental compartments. This research aimed at the development and validation of a simple and fast method for the determination of chlorpyrifos concentrations in water by means of a gas chromatograph with electron capture detection (GC/ECD), and to investigate chlorpyrifos dynamics of adsorption in a Rhodic Ferralsol in Southern Brazilian conditions. The developed chromatographic method was based in EPA 8141 method. Parameters to be checked for method validation were: Selectivity/specificity, linearity, precision, accuracy, robustness, limit of detection (LOD) and limit of quantitation (LOQ). Were employed the following methodologies for the validation process: ANVISA Resolution 899, DOQ-CGCRE-008 and FDA Bioanalytical Method Validation Guide. Also, through laboratory tests, the sorption dynamics of chlorpyrifos in Rhodic Ferralsol was evaluated. Thus, the soil was contaminated with increasing concentrations of chlorpyrifos, which were subjected to solid-liquid extraction with SPE cartridge Chromabond® C18 ec. The obtained results were submitted to the models of Langmuir, Freundlich, Dubinin-Radushkevich and Sips. By this method, chlorpyrifos peaks are obtained at 16.9 min, demonstrating practicality and low cost. This method exhibits precision and sensitivity, with satisfactory LQ and LQ values. The models of Langmuir, Freundlich, Dubinin-Radushkevich and Sips suggest the occurrence of simultaneous adsorption in mono and multilayer of chlorpyrifos in Rhodic Ferralsol colloids, as well as the predominance of a chemical, high energy binding process (irreversible). However, the chemisorption of chlorpyrifos is more related to the good fit found for Dubinin-Radushkevich sorption energy values (9.861 and 11.079 KJ mol-1) and Qm values estimated by Langmuir (485.55 and 389.61 µg g-1 for linear and nonlinear model).

Phytoremediation capacity, growth and physiological responses of Crambe abyssinica Hochst on soil contaminated with Cd and Pb.

The search for vegetal species regarding effectiveness in the phytoremediation of soils is of great importance, mainly in function of the great environmental problems, such as soil contamination with heavy metals, the necessity of producing more food, among others that mankind face today. This work aimed (i) to evaluate phytoremediation capacity of Crambe abyssinica Hochst and its growth in soil artificially contaminated with Cd and Pb, and (ii) to evaluate the possible impacts of crambe cultivation in contaminated soil conditions, in order to evaluate, to test, and to question the Brazilian CONAMA 420, providing important information that can be useful for governmental and environmental purposes. Two simultaneous experiments were developed, one for each metal. The soils were contaminated with salts of CdCl2 and PbCl2H2O in five doses based on the investigation values (IV) of CONAMA Resolution 420, resulting in 0; 1.5; 3; 9 and 30 mg kg-1 for Cd and 33; 90; 180; 540 and 1800 mg kg-1 for Pb. Gaseous exchange, development, nutritional composition and production of plant components, as well as phytoavailability of metals, were evaluated. The contamination with metals reduced photosynthesis, increased breathing as well as leading to a negative effect on the mineral nutrition and productivity in general; Plants cultivated in soil with Cd presented higher phytoavailability when compared to those cultivated in the Pb conditions, being found metals in all parts of the crambe plants from 1.5 mg kg- 1 of Cd in the soil; and Pb was retained only in roots, not being translocated in the plant. Cd showed higher phytoavailability, being found in all parts of the plant and Pb was retained only in the roots. Cd showed a higher phytoavailability when compared to Pb, also being found in all parts of crambe plants from dose 1.5 mg kg-1 of Cd in soil, which is an environmental problem, since in these concentrations the cultivation of crops is allowed by Brazilian legislation CONAMA 420.

Growth and accumulation of Pb by roots and shoots of Brassica juncea L.

In this study, different soil Pb concentrations [24 (control), 80, 136, 362, and 1150 mg kg-1] were used to analyze the tolerance threshold and accumulation potential of Brassica juncea L. in a pot experiment under greenhouse conditions. In addition to growth and Pb accumulation, the following contamination indices were calculated: transfer coefficient (TC), translocation factor (TF), and tolerance index (TI). Growth and Pb accumulation were determined at 60 days after emergence. The Pb concentrations were determined using the flame atomic absorption spectrometry (FAAS). The plant height was affected by soil Pb contamination, and it decreased from 1.37 to 0.83 m when the soil Pb concentration increased from 24 (control) to 1150 mg kg-1, respectively. The Pb concentration in the shoots and roots increased as the Pb concentration in the soil increased, reaching 94 mg kg-1 in shoots and 783 mg kg-1 in roots when was grown under 1150 mg kg-1 of Pb. TF was <1 at all levels of contamination. The TI values suggested that B. juncea presented Pb tolerance in Pb contaminated soils. Our findings indicate that B. juncea has the potential to accumulate Pb in soil under tropical conditions.

Salvinia auriculata in post-treatment of dairy industry wastewater.

The present study aimed to evaluate the aquatic macrophyte Savinia auriculata in post-treatment of wastewater from a dairy industry. The experiment was carried out in a greenhouse between February and March 2015. A batch system was used, each reactor was composed of polyethylene and had capacity of 250 liters of post-treated effluent. Every seven days, pH, turbidity, temperature, dissolved oxygen, chemical oxygen demand and series of solids (total, fixed and volatile) were determined in the wastewater. Besides that, the concentration of macro and micronutrients (P, N, K, Ca, Mg, Cu, Zn, Mn, and Fe) were determined in the wastewater and in plant tissue before and after the experiment. The results showed efficiency in the decrease of N, P, turbidity, pH, solids (ST, SF) and inefficiency in the reduction of volatile solids in the wastewater. The concentration of COD, Ca, Mn, Mg, and Fe increased at the end of the experiment. Due to the absorption of some nutrients such as N and P it is possible to conclude that Salvinia auriculata is a good option for the post-treatment of the wastewater from dairy industry. However, plant senescence promotes the elevation of some elements in the effluent because in this process, nutrients that were previously retained in the plant tissue are inserted into the wastewater again. Because of this it is necessary to remove plants of the reactor in the beginning of the process of senescence.

Pistia stratiotes in the phytoremediation and post-treatment of domestic sewage.

This work aimed to evaluate the potential of phytoremediation using Pistia stratiotes as a plant for post-treatment of wastewater from domestic sewage. The experiment was conducted at Toledo-PR, Brazil, for 42 days, in a pilot scale model. In order to evaluate the efficiency of Pistia as a post-treatment of domestic sewage, parameters such temperature, pH, turbidity, total solids, COD, Ntotal and Ptotal contents were determined in the effluent, as well as the total contents of K, Ca, Mg, Cu, Zn, Fe, Mn, Cd, and Pb. The bioaccumulation of K, Ca, Mg, Cu, Zn, Fe, Mn, Cd, and Pb in the living tissues of P. stratiotes have also been detected. The results demonstrate efficiency removal of turbidity, Ntotal, Ptotal and COD of 98.5, 100, 100, and 79.18%, respectively. The effluent contents of nutrients and toxic metals fluctuated during the study. This can have occurred due to photosynthetic activities of microorganisms and the plant senescence. The evaluation of some parameters in the effluent, such as temperature, DO, and organic matter, influenced these facts. Low levels of DO were observed, in function to the physical barrier of macrophytes in water surface, preventing the entry of air and light. The use of P. stratiotes proved to be a good complement for post-treatment of wastewater from domestic sewage.

Influence of hydrological flows from tropical watersheds on the dynamics of Cu and Zn in sediments.

This work aimed to evaluate, on a spatial and temporal scale, the effect of the flow on the concentrations of Cu and Zn in sediments from two water bodies (the Alvorada and Mandaguari Rivers). Five sediment-sampling periods were conducted, under four different streams in each sampling point (shallow/fast (SF), shallow/slow (SS), deep/fast (DF), deep/slow (DS)). Each sampling point represented the spring, the middle, and the mouth of the evaluated rivers. Some climatic variables were also evaluated, such as monthly temperature and rainfall. In addition, temperature, pH, dissolved oxygen (DO), and total solids were evaluated. Cu and Zn concentrations were obtained by FAAS. Cu and Zn levels are affected by the speed and depth of the water column. The quality of the sediments is affected by human activities in the surroundings, and according to legislation, levels of Cu and Zn in sediments offer risks of medium and high effects to aquatic biota. The highest accumulation of Cu in sediments occurs during October (221 mg kg-1) and December 2015 (225 mg kg-1), which coincides with the period of implantation of the soybean crop in the region, as well as the rain period. The increase of Cu in these periods suggests the occurrence of erosion. It can be concluded that Cu and Zn are found in large quantities in sediments, offering risk to the aquatic organisms. Cu levels exhibited direct relation with the sampling periods, with higher concentrations in rainy periods, while Zn concentrations suffer influence of the water column velocity and depth.

Removal of toxic metals using endocarp of açaí berry as biosorbent.

The effectiveness of açaí endocarp as biosorbent for removal of Cd2+, Pb2+ and Cr3+ from single solute solutions was analyzed. The biomass of açaí endocarp was characterized by scanning electron microscopy, infrared spectroscopy and determining the point of zero charge. The optimum conditions for adsorption process were obtained at solution pH 6.0 for Cd(II) removal, pH 5.0 for Pb(II) removal, and, pH 4.0 for Cr(III). Furthermore, the average optimum efficiency of biosorbent in the optimum conditions was 8, 20 and 12 g of biosorbent per litre of contaminant solution, respectively, for Cd(II), Pb(II) and Cr(III). The best dynamic equilibrium time was reached at 60 min and Langmuir's model had the best fit for Cd(II) and Cr(III) biosorption, indicating a monolayer adsorption. Freundlich's model exhibited the best fit for Pb(II) ion. Elution rates were low, indicating a strong metal interaction with the adsorbent's surface. Thermodynamic parameters showed a spontaneous and endothermal process in the case of Cd(II) and Pb(II) ions, but not for Cr(III) ion, which appears to be an exothermic process. Results show that the use of the açaí biosorbent may be a promising alternative for the remediation of polluted water, due to its low cost and highly availability.