The sustainable operation of hydroponic systems depends on maintaining the chemical stability of circulating nutrient solutions and preventing the accumulation of toxic compounds. The accumulation of phytotoxic ammonium, heavy metals, and organic metabolites in recirculating nutrient solutions remains one of the key challenges limiting the efficiency, sustainability, and scalability of hydroponic cultivation. This review provides a comprehensive comparative analysis of zeolites, activated carbons (ACs), and their functionalized and composite forms as key sorbents for nutrient management, contaminant removal, and environmental safety in hydroponic cultivation. Natural zeolites, with their well-defined crystalline structure and high ion-exchange selectivity toward ammonium and heavy metal cations, enable effective NH₄⁺/K⁺ balance regulation and phytotoxicity mitigation. ACs, characterized by high specific surface area and tunable surface chemistry, complement zeolites by offering extensive adsorption capacity for organic compounds, root exudates, and pesticide residues, thereby extending the operational lifespan of nutrient solutions and improving overall system performance. Further advancements include the integration of zeolites and ACs with two-dimensional (graphene, g-C₃N₄) and three-dimensional (MOF, COF) frameworks, yielding multifunctional materials that combine adsorption, ion exchange, photocatalysis, and nutrient regulation. Transition-metal modification, particularly with Fe, Mn, Cu, Ni, and Co, introduces redox-active centers that enhance sorption, catalysis, and phosphate stabilization. The comparative synthesis reveals that the combined application of zeolite- and carbon-based composites offers a synergistic strategy for developing adaptive and low-waste hydroponic systems. From a techno-economic and environmental standpoint, the judicious application of these materials paves the way for more resilient, efficient, and circular hydroponic systems, reducing fertilizer and water consumption, lowering contaminant discharge, and enhancing food security. This systematic review was conducted according to the PRISMA 2020 guidelines. Relevant studies were identified through Scopus, Web of Science, and Google Scholar databases using specific inclusion and exclusion criteria.

The transportation sector significantly contributes to greenhouse gas (GHG) emissions and remains a key research focus on emission quantification and mitigation. Although numerous models exist for estimating vehicle-based emissions, most lack accuracy at regional scales, particularly in remote or underdeveloped areas, including backcountry national parks and mountainous regions lacking basic infrastructure. This study addresses that gap by developing and applying a terrain-adjusted, segment-based methodology to estimate GHG emissions from tourist vehicles in Altai Tavan Bogd National Park, one of Mongolia’s most remote protected areas. The proposed method uses Tier 1 IPCC emission factors but incorporates field-segmented route analysis, vehicle categorization, and terrain-based fuel adjustments to achieve a spatially disaggregated Tier 1 approach. Results show that carbon dioxide (CO₂) emissions increased from 118.7 tons in 2018 to 2239 tons in 2024. Tourist vehicle entries increased from 712 in 2018 to 13,192 in 2024, with 99.1% of entries occurring between May and October. Over the same period, cumulative methane (CH₄) and nitrous oxide (N₂O) emissions were estimated at 300.9 kg and 45.75 kg, respectively. This modular approach is especially suitable for high-altitude, infrastructure-limited regions where real-time emissions monitoring is not feasible. By integrating localized travel patterns with global frameworks such as the IPCC 2006 Guidelines, this model enables more precise and context-sensitive GHG estimates from vehicles in national parks and similar environments.

A new iodine–dextrin–lithium complex (IDLC) was synthesized and structurally characterized as a hybrid supramolecular system combining antiseptic, stabilizing, and biocompatible components. The compound integrates iodine as the primary antimicrobial agent, lithium as a coordination and stabilization element, and dextrin as a biodegradable polysaccharide matrix enabling sustained release. Physicochemical analyses confirmed the formation of a uniform, thermally stable complex. Biological evaluation revealed strong bactericidal activity, with minimum bactericidal concentrations (MBCs) ranging from 1.95 to 15.63 µg mL⁻¹ against both Gram-positive and Gram-negative pathogens, including multidrug-resistant Staphylococcus aureus and Acinetobacter baumannii. Cytotoxicity studies revealed moderate, concentration-dependent effects on human peripheral blood mononuclear cells (CC₅₀ = 0.23–0.48 mg/mL; 11.7–24.4 μg I/mL) and low toxicity toward MDCK cells (CC₅₀ = 10–20 mg/mL; 507–1014 μg I/mL), confirming a favorable safety profile. IDLC exhibited cytotoxic effects on tumor cell lines (HepG2, HeLa, AGS, K562, and H9) as well as on the normal MeT-5A cell line; however, the CC₅₀ values are similar, and selectivity indices are close to 1, indicating no selective cytotoxicity toward tumor cells. Thus, IDLC demonstrates non-specific cytotoxicity at high concentrations, consistent with its iodine content. The research confirms that iodine can be effectively stabilized within a dextrin-lithium framework to yield a biologically active, thermally resistant complex, suitable for pharmaceutical use.

Iodine deficiency remains a significant nutritional problem, which stimulates the search for sustainable approaches to biofortification of vegetable crops. The aim of the work was to develop a "smart" bio-iodine fertilizer based on the organoiodide complex 1-carboxy-2-phenylethan-1-aminium iodide 2-azaniumyl-3-phenylpropanoate (PPI) and highly porous biochar from agro-waste, assessing its efficiency on the parsley model. PPI was synthesized and characterized (IR/UV spectroscopy, thermal analysis), biochar was obtained by KOH activation and studied by low-temperature nitrogen adsorption (S_BET) methods, as well as standard physicochemical characterization. The granulated composition PPI + biochar (BIOF) was tested in pot experiments in comparison with KI and control; The biomass of leaves and roots, iodine and organic nitrogen content, and antioxidant indices (ascorbic acid, total polyphenols, antioxidant activity) were assessed. BIOF provided a significant increase in yield and nutrition: leaf mass reached 86.55 g/plant versus 77.72 g/plant with KI and 65.04 g/plant in the control; root mass — up to 8.25 g/plant (p<0.05). Iodine content in leaves and roots increased to 11.86 and 13.23 mg/kg (d. w.), respectively, while organic nitrogen levels increased simultaneously (57.37 and 36.63 mg/kg). A significant increase in the antioxidant status was noted (ascorbic acid 36.46 mg/100 g dry weight; antioxidant activity 44.48 mg GA/g; polyphenols 23.79 mg GA/g). The presented data show that the combination of PPI with activated biochar forms an effective platform for controlled supply of iodine to plants, increasing the yield and functional qualities of products; the prospects for implementation are associated with field trials and dosage optimization.

A new iodine-dextrin-lithium complex (IDLC) was synthesized and structurally characterized as a hybrid supramolecular system combining antiseptic, stabilizing, and biocompatible components. The compound integrates iodine as the primary antimicrobial agent, lithium as a coordination and stabilization element, and dextrin as a biodegradable polysaccharide matrix enabling sustained release. Physicochemical analyses confirmed the formation of a uniform, thermally stable complex. Biological evaluation revealed strong bactericidal activity, with minimum bactericidal concentrations (MBC) ranging from 1.95 to 15.63 µg ml-1 against both Gram-positive and Gram-negative pathogens, including multidrug-resistant Staphylococcus aureus and Acinetobacter baumannii. The complex also demonstrated inhibitory effects in virus-infected MDCK cell cultures. Cytotoxicity studies showed CC50 = 0.23-0.48 mg ml-1 on human MNCs and more than 10 mg ml-1 on MDCK cells, confirming low toxicity. The results of the study on the cytotoxicity of IDLC suggest a cytotoxic effect on tumor cell lines such as HepG2, HeLa, AGS, K562, and H9, as well as normal cell lines MeT-5A. Therefore, it can be estimated that IDLC has the potential to be a new drug with antitumor activity against these cell lines. The research confirms that iodine can be effectively stabilized within a dextrin-lithium framework to yield a biologically active, thermally resistant complex, suitable for pharmaceutical use.

This study evaluates the effectiveness of natural zeolite (Shankhanai deposit, Kazakhstan) as a functional hydroponic substrate compared to a commercial foamed-glass control (GrowPlant). Using the Nutrient Film Technique (NFT), we assessed the growth and metabolic responses of Medicago sativa L. and three cultivars of Lactuca sativa L. Brunauer–Emmett–Teller (BET) analysis confirmed that zeolite (particle size 3.70 ± 1.20 mm) possesses a high specific surface area (21.80 m²/g), significantly exceeding the control (0.49 m²/g). This structure ensured superior moisture retention and cation exchange, even after a moderate decrease in surface area to 16.66 m²/g post-cultivation due to organic pore-filling. In M. sativa experiments, zeolite increased seedling viability and promoted a more branched root system compared to the artificial substrate. Gas chromatography–mass spectrometry (GC–MS) metabolic profiling of L. sativa revealed a significant substrate-driven reprogramming: zeolite increased the relative proportion of fatty acids and their derivatives (up to +51.27% in May King variety roots), suggesting membrane-protective adaptation. Genotype-specific responses were observed, with the Yeralash cultivar showing increased polyol synthesis (+2.93%) for osmoregulation. The results demonstrate that natural zeolite is an efficient, stable substrate for intensive hydroponics, optimizing root development and physiological stability through enhanced nutrient and water management.