In this work, we report the synthesis and characterization of new amorphous graphene-like TiO2/chitosan carbon microspheres and its performance as photocatalyst. Four different carbon chitosan microspheres materials were obtained based on the distinctive procedure to incorporate TiO2 and TiOSO4 to chitosan structure by pyrolysis at 600 °C. Detailed characterizations were carried out using many different techniques, as thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), scanning electron miscroscopy/energy dispersive X-ray spectroscopy (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N2 adsorption-desorption, and the obtained materials show an amorphous and a graphene-like structure, which improve the photocatalytic activity. The synthesized materials promoted a fast degradation of three micropollutants under UV-A radiation and, in all cases the degradation rate was approximately 98% at 30 min of reaction, being superior to the P-25 TiO2 efficiency. Due to the amorphous graphene-like structure, all the materials present low adsorption capacity, the high photocatalytic efficiency can be attributed to the material structure that promotes the effective charge separation which reduces the recombination electron/hole, enhancing the photocatalytic efficiency.

Cannabis sativa has many promising medicinal applications for the mitigation, or even cure, of chronic diseases. The high bioaccumulation potential of C. sativa enables its use for the phytoremediation and detoxification of soil, may increase the levels of inorganic elements in products such as cannabidiol (CBD) extracts being necessary the evaluation/monitoring of the level of inorganic components, mainly the toxic species in these formulations. An analytical method employing graphite furnace atomic absorption spectrometry (GFAAS) was developed for the quantification of Pb, As, and Cd in commercial CBD extracts and homemade samples. The alkaline solubilization was employed in agreement with the external analytical curve, in a robust method. The limits of quantification were 0.26 (Pb), 0.067 (As), and 0.011 µg g-1 (Cd), with satisfactory accuracy (80-120%) and relative standard deviation (RSD) values < 7%. The CBD extracts presented levels of Pb, As and Cd below the maximum limits established by regulatory agencies.

Rice husk ash (RHA) is a waste material produced in large quantities in many regions worldwide, and its disposal can be problematic. This work describes a method for using RHA to synthesize silicon and potassium slow-release fertilizer. The extraction of silica from RHA was accomplished by alkaline leaching with KOH. Different KOH concentrations and reaction times were evaluated and the best production of K2SiO3 solution was achieved using 6 mol L-1 and 6 h, respectively. The fertilizer was synthesized by the reaction of K2SiO3 with KAlO2 in aqueous medium, followed by calcination at 500 °C. X-ray fluorescence (XRF) and X-ray diffraction (XRD) analyses indicated that the fertilizer composition was similar to mineral kalsilite. Solubility essays indicated lower K+ and Si4+ release percentage in neutral medium. Kinetic mechanisms of release tests can be well explained by the pseudo-second order model. The proposed synthesis seems to be a viable process offering economic and environmental benefits.

This work describes the removal of pesticides from water using activated and magnetized biochars produced from exhausted husk, and dry tannin from barks of black wattle (Acacia mearnsii De Wild.). These materials were characterized using chemical, spectroscopic, thermal, solid structure and surface area techniques. The activated and magnetized biochars were effective in removing the pesticides thiacloprid and thiamethoxam from both ultrapure water and Marcela Water Reservoir, Itabaiana, Sergipe State, Brazil. At the longest time examined, the amounts of thiacloprid and thiamethoxam adsorbed per gram of activated biochar adsorbent were 1.02 and 0.97 mg, respectively, while values of 0.73 mg (thiacloprid) and 0.40 mg (thiamethoxam) were obtained using magnetized biochar. A pseudo-second order model correctly described the kinetics of adsorption of both pesticides (R(2) ≥ 0.922). Desorption experiments revealed that the spent biochars could not be easily regenerated, which indicated that the forces holding the adsorbed fluid molecules to the solid surface were relatively strong.

In this study were analyzed the main lines of health care waste at the Hospital of the Federal University of Paraná (HC/UFPR), performing an inventory that aims from awareness, characterization, until a viable wastewater treatment proposal for the institution. In this context, were emphasized physical and chemical analyses parameters, inorganic species following the legislation, as well as some chemical analysis used as support for the investigation of the environmental standard of hospital wastewater. The UFPR Clinical Hospital has a health care waste management plan, which is focused on the issue of solid waste. Thus, there are no policies, procedures and specific supervision for managing wastewater, which causes the waste to be disposed directly in the sewage network. At work in question was the physicochemical characterization, inorganic species other relevant chemical species and toxicological analysis of four collection points. Depending on the physical and chemical parameters, phenols and monitored toxicological analysis, one realizes that the hospital sewage characteristics are different from domestic sewage, which in principle suggests the need for special treatment. In this work, the behavior of the wastewater points of HC/UFPR against three types of treatment. The tests performed by the method of activated carbon, Fenton and photoFenton process.