Optimization of the Photo-Fenton process for the effective removal of chemical oxygen demand and phenols in portable toilet wastewater: A treatment study under real world conditions.

Wastewater from portable toilets (WWPT) is characterized by a high content of organic matter and a variety of chemical compounds that retain bad odors, especially phenols, a type of pollutant that is difficult to degrade by conventional treatments; in addition, it is persistent, toxic, and accumulates in the aquatic environment. Although different successful experiences with the use of Photo-Fenton are reported in the scientific domain, its application in WWPT is scarce and warrants study due to the wide use of portable toilets. The objective of this study was to evaluate the Photo-Fenton oxidation process in the removal of organic matter expressed as COD in a WWPT, as well as the reduction of phenols and BOD5. The experimental runs were carried out in a 0.50 L batch reactor to evaluate the effect of the factors (H2O2: 0.019, 25.56, 40.67, 87.24, 148.91, 174.45 g L-1 and pH: 2.80, 3.00, 3.27, 4.40, 5.53, 6.00 UNT) on COD removal and sludge production. It was found that the optimum operating conditions of pH 4.72 and H2O2 dosage of 174.45 g L-1 reduced the concentration of phenols by 97.83 % and 95.49 % of COD. In addition, 98.01 % of BOD5 was reduced, resulting in a biodegradability ratio (BOD5/COD) of 0.23 compared to the untreated wastewater of 0.53. From a cost perspective, the use of Photo-Fenton to treat wastewater under these conditions would be US$ 1.15 per liter.

Development of antimicrobial starch-based composite films reinforced with soybean expeller for sustainable active packaging applications.

In this study, the influence of glycerol and sonicated soybean expeller (SSE) on composite edible films supporting natamycin and nisin was investigated using Response Surface Methodology. Assessments were conducted on mechanical properties, moisture content, water solubility (SW), and color. Optimal results were achieved with 0.46% SSE and 1.4% glycerol, yielding a maximum tensile strength (TS) of 1.0 ± 0.1 MPa and a minimum SW of 19.0 ± 0.3%. SSE had no impact on Tg values (82-89 °C), while antimicrobials reduced Tg (70-73 °C) due to increased water retention. Water vapor permeability was (2.5 ± 0.2) × 10-9  -1 s-1 Pa-1. FTIR analysis revealed strong component interactions. The composite films demonstrated biodegradability in compost after seven days and effective action against Listeria innocua and Saccharomyces cerevisiae. These findings suggest that these materials hold promise as active films for food preservation. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-023-01516-6.

Green chemistry production of biopolymeric film-derived biomaterial prepared using natural alginate and vanillin compounds for application as a biocurative.

The present work presents the results obtained in the production of vanillin-doped alginate biopolymeric film using green chemistry methodology. Alginate dressings are already a therapeutic reality, but they act only by maintaining the appropriate environment for healing. In order to improve their properties, the incorporation of vanillin was proposed due to its antioxidant and antimicrobial potential. Different biopolymeric films were produced employing the experiment planning through response surface analysis, which allowed determining the best region for a medium value of solubility and high degree of swelling. This region refers to values above 0.07 g of CaCl2 and concentrations above 0.024 g of vanillin, triggering solubility between 25 and 30% and a degree of swelling above 100% and with fixed values of alginate (0.85 g). Such data are related to experiments (A), (B), and (C) listed in Table 1. Regarding the optimization of the process, the normal boundary intersection (NBI) method allowed the analysis of concave regions, predicting the optimal points and generating the Pareto chart with equidistant limits. The antimicrobial test allowed observing the antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa microorganisms from the biopolymeric films, as well as a solution of vanillin with calcium chloride and glycerol obtaining a halo of inhibition only in the presence of vanillin, and there was no significant difference between the results obtained in the experiments (A) and (B). The thermal analyses showed that the material has thermal stability in the ideal temperature range (~ 25 °C) for application as a biocurative. We preliminarily concluded that the alginate biopolymeric film doped with vanillin prepared using green chemical methodology presents antimicrobial properties and thermal stability that indicate its potential use as biocurative.

Chitosan (CS)/Hydroxyapatite (HA)/Tricalcium Phosphate (ß-TCP)-Based Composites as a Potential Material for Pulp Tissue Regeneration.

This research focused on developing new materials for endodontic treatments to restore tissues affected by infectious or inflammatory processes. Three materials were studied, namely tricalcium phosphate ß-hydroxyapatite (ß-TCP), commercial and natural hydroxyapatite (HA), and chitosan (CS), in different proportions. The chemical characterization using infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the composition of the composite. Scanning electron microscopy (SEM) demonstrated that the design and origin of the HA, whether natural or commercial, did not affect the morphology of the composites. In vitro studies using Artemia salina (A. salina) indicated that all three experimental materials were biocompatible after 24 h, with no significant differences in mortality rate observed among the groups. The subdermal implantation of the materials in block form exhibited biocompatibility and biodegradability after 30 and 60 days, with the larger particles undergoing fragmentation and connective tissue formation consisting of collagen type III fibers, blood vessels, and inflammatory cells. The implanted material continued to undergo resorption during this process. The results obtained in this research contribute to developing endodontic technologies for tissue recovery and regeneration.

Properties and Biodegradability of Films Based on Cellulose and Cellulose Nanocrystals from Corn Cob in Mixture with Chitosan.

The increase in consumer demand for more sustainable packaging materials represents an opportunity for biopolymers utilization as an alternative to reduce the environmental impact of plastics. Cellulose (C) and chitosan (CH) are attractive biopolymers for film production due to their high abundance, biodegradability and low toxicity. The objective of this work was to incorporate cellulose nanocrystals (NC) and C extracted from corn cobs in films added with chitosan and to evaluate their properties and biodegradability. The physicochemical (water vapor barrier, moisture content, water solubility and color) and mechanical properties of the films were evaluated. Component interactions using Fourier-transform infrared (FTIR) spectroscopy, surface topography by means of atomic force microscopy (AFM), biodegradability utilizing a fungal mixture and compostability by burying film discs in compost were also determined. The C-NC-CH compared to C-CH films presented a lower moisture content (17.19 ± 1.11% and 20.07 ± 1.01%; w/w, respectively) and water vapor permeability (g m−1 s−1 Pa−1 × 10−12: 1.05 ± 0.15 and 1.57 ± 0.10; w/w, respectively) associated with the NC addition. Significantly high roughness (Rq = 4.90 ± 0.98 nm) was observed in films added to NC, suggesting a decreased homogeneity. The biodegradability test showed larger fungal growth on C-CH films than on CH films (>60% and <10%, respectively) due to the antifungal properties of CH. C extracted from corn cobs resulted in a good option as an alternative packaging material, while the use of NC improved the luminosity and water barrier properties of C-CH films, promoting strong interactions due to hydrogen bonds.

Physicochemical and biological properties of nanohydroxyapatite grafted with star-shaped poly(ε-caprolactone).

To overcome the disadvantages generated by the lack of interfacial bonding between hydroxyapatite nanocrystals (HAPN) and agglomeration of particles in the development of biodegradable nanocomposites a chemical grafting method was applied to modify the surface of HAPN through grafting of the three-arms star-shaped poly(ε-caprolactone) (SPCL) onto the nanoparticles. The chemical grafting of SPCL onto HAPN (SPCL-g-HAPN) has been investigated using Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy (TEM), photoelectron spectroscopy, X-ray diffraction, zeta potential (ZP) and contact angle (CA). TEM micrographs of the SPCL-g-HAPN revealed the existence of hybrid organic/inorganic (O/I) nanoscale domains. The results of albumin (HSA) and fibrinogen (HFb) adsorption indicate resistance to HFb adsorption by SPCL-g-HAPN relatively to unmodified HAPN. The ZP and CA measurement suggest a heterogeneous topology for SPCL-g-HAPN likely due to the existence of hydrophobic-hydrophilic regions on the nanocomposite surface. The enzyme degradation by cholesterol esterase and lipase indicates that the rates of hydrolysis for SPCL-g-HAPN were very slow relative to the SPCL/HAPN blends. The in vitro biological studies showed that the human osteoblast-like cells (MG-63) cells had normal morphology and they were able to attach and spread out on SPCL-g-HAPN surfaces. A higher overall cellular proliferation was observed on SPCL-g-HAPN scaffolds compared to pure HAPN or SPCL materials.

Biopackaging Potential Alternatives: Bioplastic Composites of Polyhydroxyalkanoates and Vegetal Fibers.

Initiatives to reduce plastic waste are currently under development worldwide. As a part of it, the European Union and private and public organizations in several countries are designing and implementing regulations for single-use plastics. For example, by 2030, plastic packaging and food containers must be reusable or recyclable. In another approach, researchers are developing biopolymers using biodegradable thermoplastics, such as polyhydroxyalkanoates (PHAs), to replace fossil derivatives. However, their production capacity, high production costs, and poor mechanical properties hinder the usability of these biopolymers. To overcome these limitations, biomaterials reinforced with natural fibers are acquiring more relevance as the world of bioplastics production is increasing. This review presents an overview of PHA-vegetal fiber composites, the effects of the fiber type, and the production method's impact on the mechanical, thermal, barrier properties, and biodegradability, all relevant for biopackaging. To acknowledge the behaviors and trends of the biomaterials reinforcement field, we searched for granted patents focusing on bio-packaging applications and gained insight into current industry developments and contributions.

Treatment of a clinical analysis laboratory wastewater from a hospital by photo-Fenton process at four radiation settings and toxicity response.

The photo-Fenton process was performed with four radiation settings to treat clinical analysis laboratory wastewater (CALWW) from a hospital, with the aim of evaluating its treatability and acute toxicity response in Daphnia magna and Lactuca sativa. The experiments were performed in a borosilicate bench-scale conventional reactor for 320 min. The light radiation was suspended 13 cm from the CALWW surface for mild radiation or immersed into the matrix for intense radiation. All photo-Fenton experimental conditions were set at pH 3.0, 15 mg L-1 of Fe2+, and initial H2O2 of 300 mg L-1. The initial Fe2+ concentration was converted to Fe3+ ion in the first 15 min of photooxidation for all processes. Furthermore, the intense radiation processes regenerated Fe2+ faster than other systems. Neither mild UVA-Vis nor mild UVC-Vis radiation significantly treated the organic matter or phenols. However, mild UVC-Vis resulted in a higher biodegradability transformation rate (biochemical oxygen demand/chemical oxygen demand 0.51), indicating that it could treat more recalcitrant organic matter than mild UVA-Vis. Intense radiation proved to be more efficient, with a chemical oxygen demand removal rate of 95% for intense UVA-Vis and 99% for intense UVC-Vis treatments. All treatments reduced acute toxicity in D. magna. Moreover, photo-Fenton treatment by intense UVA-Vis decreased toxicity ~98%, compared to mild and intense UVC-Vis, ~75%. Both of the mild radiation treatments inhibited the germination of L. sativa seeds. The intense UVA-Vis photo-Fenton treatment was the only setting that removed phytotoxicity, resulting in a non-significant effect, and the intense UVC-Vis treatment inhibited the seed growth.

Tube-in-tube membrane photoreactor as a new technology to boost sulfate radical advanced oxidation processes.

This work proposes a tube-in-tube membrane photoreactor, operated in a continuous-mode, to boost the efficiency of peroxydisulfate (PDS), through the photolytic (UV-C radiation) and photocatalytic (TiO2-P25) processes. This new technology can efficiently facilitate the transportation of PDS to the catalyst surface and water to be treated. The ultrafiltration tubular ceramic membrane was used as support for the TiO2-P25 and oxidant-catalyst/water contactor. Tests were performed using a synthetic solution and a municipal secondary effluent, both spiked with a pharmaceutical mix solution (paracetamol (PCT), furosemide (FRS), nimesulide (NMD), and diazepam (DZP); 200 µg L-1 of each). At steady-state regime, the UVC/S2O82-/TiO2 system, with radial PDS addition, showed the highest removal of pharmaceuticals in both matrices. Furthermore, twenty-two transformation products (TPs) were identified by applying LC-QTOF MS technique. Hence, the transformation pathways including hydroxylation in aromatic moiety by an electrophilic attack, electron transfer reactions, cleavage of C-O, C-N bond, H-abstraction and ring opening were proposed. TPs chemical structures were evaluated by in silico (Q)SAR approach using TOXTREE and EPI Suite™ software.

Production of Poly-3-Hydroxybutyrate (P3HB) with Ultra-High Molecular Weight (UHMW) by Mutant Strains of Azotobacter vinelandii Under Microaerophilic Conditions.

Poly-3-hydroxybutyrate (P3HB) is a biopolymer, which presents characteristics similar to those of plastics derived from the petrochemical industry. The thermomechanical properties and biodegradability of P3HB are influenced by its molecular weight (MW). The aim of the present study was to evaluate the changes of the molecular weight of P3HB as a function of oxygen transfer rate (OTR) in the cultures using two strains of Azotobacter vinelandii, a wild-type strain OP, and PhbZ1 mutant with a P3HB depolymerase inactivated. Both strains were grown in a bioreactor under different OTR conditions. An inverse relationship was found between the average molecular weight of P3HB and the OTRmax, obtaining a polymer with a maximal MW (8000-10,000 kDa) from the cultures developed at OTRmax of 5 mmol L-1 h-1 using both strains, with respect to the cultures conducted at 8 and 11 mmol L-1 h-1, which produced a P3HB between 4000 and 5000 kDa. The increase in MW of P3HB was related to the activity of enzymes involved in the synthesis and depolymerization. Overall, our results show that it is possible to modulate the average molecular weight of P3HB by manipulating oxygen transfer conditions with both strains (OP and PhbZ1 mutant) of A. vinelandii.

Chemical and toxicological evaluation along with unprecedented transformation products during photolysis and heterogeneous photocatalysis of chloramphenicol in different aqueous matrices.

As the presence of antibiotics in environmental waters enhances antimicrobial resistance, photolysis and heterogeneous photocatalysis of chloramphenicol (CAP) were evaluated in deionized water (DW) and in sewage treatment plant (STP) effluent under black light and solar irradiation. Processes were compared in terms of CAP degradation, reaction kinetics, and electrical energy per order, as well as regarding theoretical toxicity, biodegradability, carcinogenicity, and mutagenicity of transformation products (TPs). Rate constants obtained under photolysis (0.008 min-1) and heterogeneous photocatalysis (0.18 min-1) only differed in DW. This is due to the generation of photo-active reactive oxygen species (HO· and HO2·-/O2·-) under photolysis in STP effluent, as verified by experiments in the presence of 2-propanol and chloroform. Natural organic matter and HCO3- were the main responsible for reducing CAP degradation in STP effluent. Fifteen TPs were identified during both processes in DW, 13 of which are unprecedented. TPs were formed mainly via HO· preferential attack on the aromatic ring and on the α-carbon, and some of them were classified as persistent and toxic, genotoxic, or carcinogenic by Toxtree software. Results confirm that solar photocatalysis is less costly than to photocatalysis under black light for wastewater treatment.

Solar photo-Fenton treatment of the anti-cancer drug anastrozole in different aqueous matrices at near-neutral pH: Transformation products identification, pathways proposal, and in silico (Q)SAR risk assessment.

Anastrozole (ANZ) is a breast cancer drug that was introduced onto the pharmaceutical market in the 1990s and is still one of the most widely consumed cytotoxic compounds. Due to the persistence of the drug, its continued presence after passing through wastewater treatment plants can lead to harm to aquatic environments. The present study investigates use of the solar photo-Fenton (SPF) process applied for ANZ degradation, considering the fate of ANZ and its transformation products (TPs). The SPF process was performed using different concentrations of ferrous iron (Fe2+) and H2O2 in solutions produced with deionized water (DW) and hospital wastewater (HWW), at pH close to neutrality. When solar irradiation in the SPF process was carried out the best ANZ removal rates were found under the following conditions: (i) for the DW matrix, [ANZ]0 = 50 µg L-1, [Fe2+] = 5 mg L-1, and [H2O2]0 = 25 mg L-1, achieving 95% primary ANZ elimination; (ii) for the HWW matrix, [ANZ]0 = 50 µg L-1, [Fe2+] = 10 mg L-1(multiple additions), and [H2O2]0 = 25 mg L-1, achieving 51% primary ANZ elimination. LC-QTOF MS analysis allowed to identify tentatively five transformation products (TPs) formed during the ANZ degradation process in DW, and two TPs when HWW was used. The main proposed degradation pathways were demethylation and hydroxylation. Different in silico models free available (quantitative) structure-activity relationship ((Q)SAR) software were used to predict the ecotoxicities and environmental fates of ANZ and the TPs. The in silico (Q)SAR predictions indicated that ANZ and the TPs were non-biodegradable compounds. In silico (Q)SAR predictions for mutagenicity and carcinogenicity end-points identified some TPs that require further study. Attention is drawn to the formation of several TPs for which statistical and rule-based positive alerts for mutagenic activities were found, requiring further confirmatory in vitro validation tests.

Degradation of ciprofloxacin using a low-grade titanium ore, persulfate, and artificial sunlight.

In this study, the magnetic fraction (MF) of a low-grade titanium ore (TO) was successfully used as an alternative Fe2+ source in five reuse cycles, in combination with persulfate (PS) and simulated sunlight (SSL) for the degradation of ciprofloxacin (CIP). The best response of the CIP initial concentration, irradiation time, and doses of MF and PS to degrade completely this pollutant were determined based on an experimental design. However, the individual application of MF, PS, or SSL fails to achieve this goal at the optimal experimental condition. Furthermore, the MF-PS-SSL system showed a higher production of sulfate radicals and a concentration of dissolved Fe2+ ions compared with data obtained for the MF-PS system. The best performance attained by the former system is due to the synergy produced between the photo-generated electrons, and the reaction of PS with the Fe2+ ions leached gradually from the MF, which increased sulfate radical production. After five reuse cycles of the MF, the oxidation system showed a CIP degradation of 100% in 100 min, no residual content of PS, a CIP mineralization of 6%, a marginal increase in the biodegradability (BOD5/COD ratio), a MF loss of 7.5%, and a twofold increase in toxicity; however, this parameter was lower than the effective concentration at 50% inhibition (EC50). The substitution of MF with an iron salt decreased the degradation efficiency of the antibiotic by 14%, probably owing to the immediate excess of Fe2+ in the solution, which can be oxidized to Fe3+ ions, and as a consequence of this, the production rate of the sulfate radical was also reduced.

Improving biotreatability of hazardous effluents combining ZVI, electrolysis and photolysis.

In this work, nine types of combination advanced oxidation processes/zero-valent iron (AOP-ZVI) were tested, in order to determine if any of these combinations demonstrate good chances as pretreatment for the biological degradation processes of organochlorinated pollutants. To do this, the changes undergone in the respirometric behavior, toxicity and short-term biodegradability were compared. The three AOPs studied were anodic oxidation with mixed metal oxides anodes (AO-MMO), with boron doped diamond anodes (AO-BDD) and photolysis and they were evaluated in three different modes: without any addition of ZVI, with ZVI-dehalogenation as pre-treatment and with ZVI-dehalogenation simultaneous to the AOP treatment. Clopyralid has been used as a model of chlorinated hydrocarbon pollutant. Results show that technologies proposed can successfully treat wastes polluted with clopyralid and the biological characteristics of the waste are significantly modified by dehalogenating the waste with ZVI, either previously to the treatment or simultaneously to the treatment, being the information provided by the three techniques very important in order to evaluate later combinations of the advanced oxidation technologies with biological treatments.

Influence of desorption process and pH adjustement on the efficiency of O3, O3/H2O2 and O3/UV treatment of water and soil samples contaminated by crude petroleum.

The influence of the pH and the contaminant desorption/emulsification on ozone (O3), ozone-hydrogen peroxide (O3/H2O2) and ozone-photolysis (O3/UV) oxidation reactions were performed to treat crude petroleum (CP) contaminated soil and water samples. Oxidation efficiency is also related to both free radicals formation in reaction medium (which is dependent of the pH), and contaminant availability (which is dependent of the compounds solubilization or desorption processes). Thus, batch basic processes of O3/H2O2 or O3/UV were improved with sonication system and surfactant addition. In the case of O3/H2O2 process, the reactions were performed at adjusted (pH = 11) and natural pH (free pH= 4-5). The effectiveness of the improved advanced oxidation processes were evaluated through the time-course analysis of the chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and total organic carbon (TOC) values. For both improved treatment processes, CP-contaminated water samples displayed higher values for TOC removal and BOD5/COD ratios than CP-contaminated soil samples. The O3/H2O2 process provided better results than the O3/UV process regarding degradation efficiency, but the former is associated with higher treatment costs due to H2O2 consumption. Overall, oxidation treatment processes increase their efficiencies when reactions are carried out associated with solubilization and desorption systems promoted by sonication/surfactant action.

Methane potential of fruit and vegetable waste: an evaluation of the semi-continuous anaerobic mono-digestion.

The anaerobic digestion (AD) of a high diversity blend of fruit and vegetable waste (FVW) generated in tropical conditions as a single substrate was performed. A continuously stirred tank reactor (CSTR) operated in semi-continuous regime was used for AD. The reactor performance was monitored with gradually increasing organic loading rates (OLRs) from 0.5 up to 5.0 gVS L-1 d-1. The biochemical methane potential (BMP) of FVW determined by batch bottles was 360 LN CH4 kgVS-1, with a biodegradability of 79%. A stable pH with an adequate level of buffering capacity was observed during the entire experiment. Methane yield indicated the best performance at an OLR of 3.0 gVS L-1 d-1, with 285 LN CH4 kgVS-1 added, reaching 79% of BMP. At an OLR over 3.0 gVS L-1 d-1 accumulation of volatile fatty acids (VFA) was detected; in particular, propionic acid was monitored, and a decreased methane yield was detected. Biogas production rate was 1.55 LN L-1 d-1 and showed linear increase according to increases in the OLR.

Treatment of biodigested coffee processing wastewater using Fenton's oxidation and coagulation/flocculation.

Biodigested coffee processing wastewater (CPW) presents a high organic load and does not meet the limits imposed by legislation (namely in Brazil) for discharge into water bodies. Anaerobic digestion generally cannot provide a satisfactory organic matter reduction in CPW as a significant fraction of recalcitrant compounds still persists in the treated effluent. So, this study aims to find alternative ways to remove refractory organic compounds from this wastewater in order to improve the biodegradability and reduce the toxicity, which will allow its recirculation back into the anaerobic digester. Three treatment approaches (Fenton's oxidation - Approach 1, Coagulation/flocculation (C/F) - Approach 2, and the combination of C/F with Fenton's process - Approach 3) were selected to be applied to the biodigested CPW in order to achieve that objective. The application of the Fenton process under the optimal operating conditions (initial pH = 5.0; T = 55 °C, [Fe3+] = 1.8 g L-1 and [H2O2] = 9.0 g L-1) increased the biodegradability (the BOD5:COD ratio raised from 0.34 ± 0.02 in biodigested CPW to 0.44 ± 0.01 after treatment) and eliminated the toxicity (0.0% of Vibrio fischeri inhibition) along with moderate removals of organic matter (51.3%, 55.7% and 39.7% for total organic carbon - TOC, chemical oxygen demand - COD and biochemical oxygen demand - BOD5, respectively). The implementation of a coagulation/flocculation process upstream from Fenton's oxidation, under the best operating conditions (pH 10-11 and [Fe3+] = 250 mg L-1), also allowed to slightly increase the biodegradability (from 0.34 to 0.47) and reduce the toxicity, whereas providing a higher removal of organic matter (TOC = 76.2%, COD = 76.5 and BOD5 = 66.3% for both processes together). Approach 1 and Approach 3 showed to be the best ones, implying similar operating costs (∼74 R$ m-3/∼17 € m-3) and constitute an attractive option for managing biodigested CPW.

Castor Bean Cake Protein-based Biodegradable Films: Gallic Acid Effect

Abstract: The objective of this work was to evaluate the effect of gallic acid (GA) concentration on some physical properties and biodegradability of films produced with proteins extracted from the castor bean cake. The films, prepared by the casting technique, showed homogeneous and brownish appearance. As the GA concentration increased (from 0 to 10 g/100 g protein), the films gradually became darker and more opaque; while the gloss had few significant differences. Solubility, tensile strength and elasticity modulus values of films varied due to changing concentrations of gallic acid. Elongation at break and water vapor permeability values did not have significant changes. A 60% mineralization value of the film containing GA was obtained at 21 days, evidencing its biodegradability. These dark and opaque films could be used in agriculture, specifically in seedling bags as the dark color decrease the incidence of light, preventing root weakening, and the seedlings can be transplanted directly without removal of the film.

An overview of nanogel-based vaccines.

Introduction: The development of more efficacious vaccines, especially subunit vaccines administered via non-invasive routes, is a priority in vaccinology. Nanogels are materials that can meet the requirements to serve as efficient vaccine delivery vehicles (in terms of thermo-sensitivity, biocompatibility, and pH-responsiveness; among others); thus there is a growing interest in exploring the potential of nanogels for vaccine development. Areas covered: Herein, a critical analysis of nanogel synthesis methodologies is presented and nanogel-based vaccines under development are summarized and placed in perspective. Promising vaccine candidates based on nanogels have been reported for cancer, obesity, and infectious diseases (mainly respiratory diseases). Some of the candidates were administered by mucosal routes which are highly attractive in terms of simple administration and induction of protective responses at both mucosal and systemic levels. Expert opinion: The most advanced models of nanogel-based vaccines comprise candidates against cancer, based on cholesteryl pullulan nanogels evaluated in clinical trials with promising findings; as well as some vaccines against respiratory pathogens tested in mice thus far. Nonetheless, the challenge for this field is advancing in clinical trials and proving the protective potential in test animals for many other candidates. Implementing green synthesis approaches for nanogels is also required.

Seasonal variation of the organic and inorganic composition of sugarcane vinasse: main implications for its environmental uses.

Sugarcane vinasse is the main waste stream of the Brazilian agroindustry. The typical composition of sugarcane vinasse gives it a high polluting potential that implies the necessity to define sustainable strategies for managing this waste. Knowledge of the inorganic and organic composition of vinasse and its seasonal variation is extremely important to conduct scientific research to define alternative managements for vinasse disposal other than fertigation. This study evaluated the variability of vinasse composition throughout the same harvesting season and among three harvesting seasons of one Brazilian annexed biorefinery (2015-2017). The contents of chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total solids (TS), suspended solids (SS), salinity (K+, Na+, Ca2+, Mg2+, Cl-, F-), nutrients (N, P, S), trace metals (Al3+, As2+, Ba2+, Cd2+, Cr3+, Co2+, Cu2+, Fe2+, Pb2+, Mn2+, Hg2+, Mo2+, Ni2+, Se2+, Zn2+), and specific soluble organic compounds (sugars, alcohols, and organic acids), as well as pH and conductivity, were monitored in 13 samples. The results indicated that sugarcane vinasse is a suitable feedstock for biological treatments, such as anaerobic digestion processes for energy recovery, as well as substrate for biomass (e.g., microalgae, energy crops, lignocellulosic biomass) growth. The application of a previous treatment makes vinasse a more environmentally friendly natural fertilizer for land fertigation.