This present study describes the investigation of new promising hybrid cryogels able to retain high amounts of antibiotics, specifically penicillin G, using chitosan or chitosan–biocellulose blends along with a naturally occurring clay, i.e., kaolin. In order to evaluate and optimize the stability of cryogels, three types of chitosan were used in this study, as follows: (i) commercial chitosan; (ii) chitosan prepared in the laboratory from commercial chitin; and (iii) chitosan prepared in the laboratory from shrimp shells. Biocellulose and kaolin, previously functionalized with an organosilane, were also investigated in terms of their potential to improve the stability of cryogels during prolonged submergence under water. The organophilization and incorporation of the clay into the polymer matrix were confirmed by different characterization techniques (such as FTIR, TGA, SEM), while their stability in time underwater was investigated by swelling measurements. As final proof of their superabsorbent behavior, the cryogels were tested for antibiotic adsorption in batch experiments, in which case cryogels based on chitosan extracted from shrimp shells seem to exhibit excellent adsorption properties for penicillin G.

Water pollution is becoming a great concern at the global level due to highly polluted effluents, which are charged year by year with increasing amounts of organic residues, dyes, pharmaceuticals and heavy metals. For some of these pollutants, the industrial treatment of wastewater is still relevant. Yet, in some cases, such as pharmaceuticals, specific treatment schemes are urgently required. Therefore, the present study describes the synthesis and evaluation of promising cryostructured composite adsorbents based on chitosan containing native minerals and two types of reinforcement materials (functionalized kaolin and synthetic silicate microparticles). The targeted pharmaceuticals refer to the ciprofloxacin (CIP) antibiotic and the carbamazepine (CBZ) drug, for which the current water treatment process seem to be less efficient, making them appear in exceedingly high concentrations, even in tap water. The study reveals first the progress made for improving the mechanical stability and resilience to water disintegration, as a function of pH, of chitosan-based cryostructures. Further on, a retention study shows that both pharmaceuticals are retained with high efficiency (up to 85.94% CIP and 86.38% CBZ) from diluted aqueous solutions.

In recent years, there have been growing concerns about finding alternatives to fossil fuels, and biomass could be one of them. To ensure the production of biogas as one of the alternative sources, the development of anaerobic digestion technologies for agricultural and animal waste is one of the promising directions. In this work, the process of biogas production from different types of solid substrates and microalgae was studied using an automatic gas flow measurement system. The biogas flow rate was monitored throughout the process. In order to use the digestate resulting from biogas production as a soil improver, the content of macroelements was analyzed.

The global food system is under increasing pressure

We face significant environmental pollution problems due to various industries, such as the aluminum industry, which generates large amounts of red mud (RM) waste, or agriculture, in which case the use of pesticides creates huge water pollution problems. In this context, the present study offers a better perspective to originally solve both environmental issues. Thus, the main target of the study referred to using RM waste as a filler for preparing composite copolymer beads. Thereafter, this can achieve significant removal of water pollutants due to their adsorption/oxidation characteristics. As evidenced by the changes in chemical structure and composition, thermal stability, morphology, and porosity, RM was homogenously incorporated in poly(acrylonitrile-co-acrylic acid) beads prepared by wet phase inversion. The final assessment for the removal of pesticides by adsorption and oxidation processes was proven successful. In this regard, 2,4-dichlorophenoxyacetic acid was chosen as a model pollutant, for which an adsorption capacity of 16.08 mg/g composite beads was achieved.

Climate change and population growth are intensifying global food security challenges by reducing agricultural productivity and increasing reliance on fertilizers. In this context, developing sustainable and economically efficient agricultural solutions becomes essential. The study presents the synthesis of an interpenetrating polymer network (IPN) of hydrogels by combining bacterial cellulose (BC) with poly(acrylic acid) crosslinked with N, N-methylene-bis-acrylamide (PAA–co–MBA) via free radical copolymerization. To explore their potential as bioactive compound carriers, an ethanolic hydroalcoholic phytoextract (EHP) obtained from Hypericum perforatum L. and Melissa officinalis L. was directly encapsulated within the IPN hydrogels. The EHP is valued for its rich bioactive profile and antifungal, antimycobacterial, and antioxidant properties. The results of rheology measurements and thermal gravimetric analysis (TGA) revealed that incorporating BC into the IPN hydrogels significantly enhanced the mechanical stiffness, thermal resistance, and overall stability of the resulting IPN structures. Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) confirmed the structural organization and the porosity of the developed composite, as well as the successful fabrication of IPN hydrogels in the EHP medium. Under optimal conditions, the IPN hydrogels exhibited a reduced swelling capacity, thereby slowing the diffusion of the bioactive agents, reducing the application frequency, and enhancing the utilization efficiency. Taken together with the controlled-release performance, these findings demonstrate the potential of BC (PAA-co-MBA) IPN hydrogels as biodegradable and sustainable carrier systems for controlled delivery applications and suggest that they may be promising candidates for hydrogel-based agricultural delivery systems.