Geochemistry and the optics of geospatial analysis as a preposition of water quality on a macroscale.

The water treatment depends exclusively on the identification of residues containing toxic chemical elements accumulated in NPs (nanoparticles), and ultrafine particles sourced from waste piles located at old, abandoned sulfuric acid factories containing phosphogypsum requires global attention. The general objective of this study is to quantify and analyze the hazardous chemical elements present in the leachate of waste from deactivated sulfuric acid factories, coupled in NPs and ultrafine particles, in the port region of the city of Imbituba, Santa Catarina, Brazil. Samples were collected in 2020, 2021, and 2022. Corresponding images from the Sentinel-3B OLCI satellite, taken in the same general vicinity, detected the levels of absorption coefficient of Detritus and Gelbstoff (ADG443_NN) in 443 m-1, chlorophyll-a (CHL_NN (m-3)), and total suspended matter (TSM_NN (g m-3) at 72 points on the marine coast of the port region. The results of inductively coupled plasma atomic-emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS) demonstrate that the leaching occurring in waste piles at the port area of Imbituba was the likely source of hazardous chemical elements (e.g., Mg, Sr, Nd, and Pr) in the environment. These leachates were formed due to the presence of coal pyrite and Fe-acid sulfates in said waste piles. The mobility of hazardous chemical elements potentiates changes in the marine ecosystem, in relation to ADG443_NN (m-1), CHL_NN (m-3), and TSM NN (g m-3), with values greater than 20 g m-3 found in 2021 and 2022. This indicated changes in the natural conditions of the marine ecosystem up to 30 km from the coast in the Atlantic Ocean, justifying public initiatives for water treatment on a global scale.

Development of a biosponge based on Luffa cylindrica and crosslinked chitosan for Allura red AC adsorption.

A new bioadsorbent from Luffa cylindrica and cross-linked chitosan was proposed in the present study. Luffa was used as a natural support medium for chitosan crosslinked with glutaraldehyde (LCsG) and epichlorohydrin (LCsE). Biosponges were applied to remove Allura red from aqueous solutions. LCsG and LCsE were produced using different concentrations of chitosan (1%, 3% and 5% (m v-1)) and crosslinking agents (0.5%, 1.0% and 1.5% (v v-1)). Based on the FT-IR spectra, functional groups characteristic of chitosan crosslinked with glutaraldehyde and epichlorohydrin confirmed the crosslinking. In addition, the biosorbent revealed highly efficient functional groups and morphology with irregularities favorable for adsorption. It was found that the increase in the percentage of glutaraldehyde and epichlorohydrin increased the sample's swelling degree, and the degree of cross-linking was greater than 80% for all LCsG. The results regarding the degree of swelling and degree of crosslinking corroborated with the evaluation of the biosponge's adsorptive potential. The Sips model predicted the equilibrium isotherms, with a maximum adsorption capacity of 89.05 mg g-1 for LCsG and 60.91 mg g-1 for LCsE. The new procedure was successful. Luffa was excellent support for chitosan, resulting in an attractive, low-cost bioadsorbent, preventing renewable sources.

Identification of hazardous nanoparticles present in the Caribbean Sea for the allocation of future preservation projects.

The deposition of remaining nanoparticles in the Caribbean Sea generates the formation of potentially dangerous elements, which influence at the imbalance of ecosystems. The detection of nanoparticles is not simple and the use of conventional methods is difficult application, which is why we highlight the immediacy and importance of this research for the areas of marine biology, urbanism, engineering and geosciences, applied in the Caribbean Sea. The general objective of this study is to evaluate the use of advanced methods for the determination of toxic nanoparticles, which can directly affect the development of marine organisms in the aquatic ecosystem in waters of the Caribbean Sea, favoring the construction of future international public policies with the elaboration of projects capable of mitigating these levels of contamination. The morphology and structure of nanoparticles were analyzed by emission scanning electron microscope with a high-resolution electron microscope. The nanoparticles smaller than 97 nm were identified in different proportions. The morphological analyses indicated nanoparticles' presence in the form of nanotubes, nanospheres, and nanofibers, which were shown in an agglomerated form. The presence of potentially hazardous elements, such as As, Cd, Pb, Mg, Ni and V were verified. In addition, the presence of asbestos in the form of minerals was confirmed, and that of titanium dioxide was found in large quantities. The results provide new data and emphasize the possible consequences to the in the Caribbean Sea, with the identification of dangerous elements (As, Cb, Pb, Hg, Ni and V), harmful to the marine ecosystem. Therefore, there is a need for strict control to reduce contamination of the Caribbean Sea and avoid risks to the ecosystem and public health, through suggestions of international public policies, through constant monitoring and the application of environmental recovery projects in this marine estuary.

Chitin-psyllium based aerogel for the efficient removal of crystal violet from aqueous solutions.

A new alternative aerogel was prepared from low-cost chitin and psyllium biopolymers to adsorb crystal violet (CV) dye from liquid media and possibly treat effluents containing other dyes. The aerogel was characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), which demonstrated that aerogel has a typical structure of amorphous materials and presented a randomly interconnected porous structure that resembles an open pore network. 2.5 g L-1 of aerogel was able to remove 86.00% of CV from solutions, and the natural pH of the CV solution was considered the more adequate for adsorption. The pseudo-second-order (PSO) model satisfactorily described the adsorption kinetics, and the Freundlich model was suitable to represent the adsorption equilibrium. The maximum experimental capacity achieved was 227.11 mg g-1, which indicates that aerogel is very efficient and competitive with several adsorbents. Tests using a simulated effluent showed that aerogel has excellent potential to treat real colored effluents.

Soil contamination in Colombian playgrounds: effects of vehicles, construction, and traffic.

The presence of potentially hazardous elements (PHEs) in playground soils is generally associated with anthropogenic sources such as vehicle traffic, industries, construction sites, and biomass burning. Studies indicate that PHEs are harmful to human health and may even be carcinogenic. Therefore, the aim of this study was to evaluate the physicochemical, morphological, and mineralogical properties of soil samples from three public playgrounds located in the cities of Bogota, Medellin, and Barranquilla. Besides, the possible impacts caused by the aerodynamics of particles in Colombian cities were verified. The morphology, composition, and structure of the nanoparticles (NPs) (< 100 nm) present in these soils were evaluated by field emission scanning electron microscopy (FE-SEM) equipped with high-precision field emission (FE) and high-resolution transmission electron microscopy (HR-TEM). Soil samples were predominantly feldspar, quartz, and, to a lesser extent, clay minerals, carbonates, and hematites. The average content of PHEs was anthropogenically enriched in relation to the upper continental crust. As and Sn showed a large spatial variation, indicating the influence of local sources, such as vehicle traffic and industries. There is an inverse relationship between the total concentrations of some elements and their leachable fractions. The accumulation of traffic-derived PHEs has a negative impact on human health and the environment, which is alarming, especially for elements such as Pb, Sb, or As. Therefore, the presence of PHEs should receive greater attention from public health professionals, and limits should be set and exposures controlled. This study includes the construction of a baseline that provides basic information on pollution, its sources, and exposure routes for humans in the vicinity of Colombia's major cities, characterized by their increasing urbanization and industrialization.

Removal of fluoride from fertilizer industry effluent using carbon nanotubes stabilized in chitosan sponge.

Adsorption of fluoride from fertilizer industry effluent using carbon nanotubes stabilized in chitosan sponge as adsorbent was evaluated. The effluent was produced in the washing of acid gases during the reaction in fertilizer production and all assays were performed using this hazardous material. Adsorbent characterization and ions interactions were elucidated from differential scanning calorimetry, thermal gravimetric analyses, X-ray diffraction, scanning electron microscopy dispersive energy X-ray spectroscopy, atomic force microscopy and X-ray photoelectron spectroscopy. The effluent presented pH 3 and its value not changed in the adsorption assays, maintaining the conditions of the process. The kinetics assays of fluoride from industry effluent were performed in different stirring rates from 100 to 300 rpm. It was observed that adsorption was initially fast reaching the equilibrium at 300 rpm in 20 min. The adsorption capacity was around 975.4 mg g-1, showing the potential of the hybrid material to remove fluoride from a real matrix. The high adsorption capacity was attributed to the chitosan functional groups and the high interaction area promoted by sponge form and the carbon nanotube. Reuse and regeneration of the CNT-CS were investigated and 5 cycles were obtained. The adsorption capacity kept similar values in all cycles.

Solid wastes from the enzyme production as a potential biosorbent to treat colored effluents containing crystal violet dye.

Sugarcane bagasse, a largely available waste worldwide, was submitted to solid-state fermentation (SSF) using the fungus Metarhizium anisopliae, aiming to produce enzymes. The solid waste generated from SSF was tested as an alternative biosorbent to treat colored effluents containing crystal violet (CV) dye. The biosorbent, here named BW (bagasse waste), was characterized, and experimental tests were performed to verify the influence of pH and dosage on the CV biosorption. Isotherms and biosorption kinetics were performed, and the biosorption thermodynamic parameters were determined. The potential of BW was also evaluated for the treatment of a simulated textile effluent. The maximum biosorption capacity was 131.2 mg g-1 at 328 K, and the Liu was the most appropriate model to represent equilibrium data. The biosorption was spontaneous and endothermic. The use of BW in the simulated effluent showed that it is an efficient material, reaching color removal values of 85%. Therefore, the sugarcane bagasse generated from SSF can be considered a potential biosorbent to remove CV from textile effluents. This finding is relevant from the total environment viewpoint, since, at the same time, SSF generates enzymes and a solid waste, which in turn can be used as biosorbent to treat colored effluents.

Separation of anthocyanins extracted from red cabbage by adsorption onto chitosan films.

Anthocyanin pigments are suitable as natural dyes for food, cosmetics and dietary supplements, due to the demand for healthier products and their antioxidant properties. This work aimed to extract the anthocyanin pigments from red cabbage and its separation of the solution by adsorption operation onto chitosan films. The anthocyanin was extracted from red cabbage in water hot at 90 °C by 15 min. Chitosan was obtained from shrimp waste, and its films were produced by casting technique (tensile strength of 25.1 ±â€¯1.9 MPa, elongation of 10.5 ±â€¯3.5% and thicknesses of 103.1 ±â€¯1.3 µm). The anthocyanin adsorption assays were performed in batch, and the highest adsorption capacity was around 140 mg g-1. The equilibrium experimental data were adjusted by Henry, Langmuir and Freundlich models, and all models showed a good fitting (R2 ≥ 0.96 and ARE ≤ 6.5%). The thermodynamic parameters represented endothermic and physical adsorption. The kinetic behavior was evaluated by empirical models, being the pseudo-first order model that showed the best fitting (R2 ≥ 0.97 and ARE ≤ 8.5%). This work presented suitable information about the anthocyanin molecules immobilization onto chitosan films and, these results could be important to the use these pigments with chitosan in different areas.

Synthesis of a bio-based polyurethane/chitosan composite foam using ricinoleic acid for the adsorption of Food Red 17 dye.

A novel bio-based polyurethane/chitosan foam (PU/chitosan) was synthesized using a polyol derived from castor oil and applied to remove Food Red 17 dye (FR17) from aqueous solutions. PU/chitosan foam presented better characteristics and adsorption potential than polyurethane foam (PU). PU/chitosan foam showed a semi-crystalline structure, with several functional groups, high porosity and good mechanical properties. These characteristics are adequate for adsorptive separations. Using identical adsorption conditions, PU/chitosan was able to remove >98% of FR17 dye from the solution, while, PU removed only 40%. The adsorption of FR17 on PU/chitosan composite foam was favored at pH 2. Pseudo-second order model was the most adequate to represent the kinetic data. The equilibrium data followed the Sips model, with a maximum adsorption capacity of 267.24 mg g-1. The adsorption process was spontaneous, favorable and endothermic. The results showed that polyurethane foams are capable to support chitosan, generating an adsorbent with better mechanical characteristics and high potential to remove anionic dyes from aqueous media.