Józef Tadeusz Haponiuk

Selective recovery of critical metals such as gallium and scandium from dilute, multicomponent process streams remains challenging due to their low concentrations and complex matrices. Here we investigate a remotely interacting intergel system based on crosslinked poly(acrylic acid) (hPAA) and poly(4-vinylpyridine) (hP4VP) hydrogels across seven mass ratios (6:0–0:6) for sorption of Ga(III) and Sc(III) from binary sulfate solutions. Inductively coupled plasma optical emission spectroscopy shows that mutual activation of the weak polyacid/polybase pair markedly enhances metal uptake, with maximum sorption degrees of 73.17% for Ga(III) at hPAA:hP4VP = 3:3 and 56.00% for Sc(III) at 2:4, corresponding to distribution coefficients up to 2726.7 mL g⁻¹ and Ga/Sc selectivity factors β up to 6.41. Sorption is well described by Langmuir-type isotherms, and desorption with 2 wt.% HNO₃ reveals an inverse sorption–release relationship, indicating stronger binding at compositions of maximal mutual activation. FTIR spectroscopy evidences inner-sphere complexation through bidentate carboxylate coordination in hPAA and M←N dative bonding in hP4VP, while TGA/DSC shows that metal-loaded hydrogels retain their structural integrity up to approximately 320–340 °C, with the onset of significant decomposition occurring at ~350 °C for hP4VP-containing samples. The composition-dependent magnitude of Ga(III)-over-Sc(III) preferential uptake—with selectivity coefficients β = K_d(Ga)/K_d(Sc) remaining greater than 1 across all seven compositions studied—is rationalized using Hard–Soft Acid–Base considerations and demonstrates that hPAA:hP4VP intergels constitute a composition-tunable platform for enhancing Ga(III) recovery and partial Ga/Sc separation from simplified sulfate media, motivating future validation in real hydrometallurgical liquors and in the presence of competing multivalent cations.

Isolating rhenium and molybdenum selectively from multicomponent acidic hydrometallurgical solutions remains problematic because of the abundance of competing cations and the low concentration of target oxoanions. This study investigates the sorption of Re(VII) and Mo(VI) oxoanions by an interpolymer system (IPS) comprising a cellulose–polyethyleneimine–glutaraldehyde (Cellulose-PEI-GA) weak-base anion exchanger and a sulfonated styrene–divinylbenzene cation-exchange resin (Lewatit MonoPlus SP112H), operating as spatially separated but solution-coupled phases. The industrial feed, a sulfuric acid leach liquor from electrostatic precipitator dust at the Zhezkazgan copper smelter, Kazakhstan (pH 1.25), was pretreated by liquid–liquid extraction with a trialkylamine-2-ethylhexanol–kerosene system followed by ammonia stripping to give an alkaline re-extract (pH 11.98) used for sorption. At the optimal 1:1 mass ratio of the two components (3:3), the IPS achieved a rhenium recovery of 77.7% (Kd = 3678 mL g⁻¹, q = 4.51 mg g⁻¹) against a markedly lower molybdenum recovery of 24.0% (Kd = 333 mL g⁻¹), giving a Re/Mo separation factor β of 8.8–15.5 across the studied compositions; this uptake exceeded the value predicted from the individual sorbents by a factor of ~2.6, indicating a cooperative rather than purely additive effect. Sorption kinetics (pseudo-first-order, pseudo-second-order and Elovich models) and diffusion mechanisms (Weber–Morris and Boyd models) were consistent with mixed film- and intraparticle-diffusion control. Desorption with hydrochloric acid recovered 91.4% of the sorbed rhenium and 89.1% of the molybdenum, and FTIR, TGA, and BET analyses (surface area increasing from 1.93 to 8.62 m² g⁻¹ for the cellulose component and from 7.21 to 8.46 m² g⁻¹ for the resin) confirmed sorbate-induced textural and compositional changes consistent with the proposed complementary anion-/cation-exchange mechanism.

This study investigates the sorption, structural, and morphological properties of an interpolymer system (IPS) based on Amberlite IR120 (H⁺) and KU-2-8 (H⁺) cation exchangers with acidic sulfonic groups (−SO₃H), applied for the selective sorption of dysprosium (Dy³⁺), neodymium (Nd³⁺), and samarium (Sm³⁺) ions from aqueous solutions. The sorption activity was evaluated for seven systems with molar ratios ranging from 6:0 to 0:6 over a contact time of up to 48 h within a pH range of 2.0 to 5.0. The interpolymer pair with a molar ratio of 5:1 demonstrated the highest sorption efficiency at pH 5.0, yielding extraction degrees of 61.8% for Dy³⁺, 62.0% for Nd³⁺, and 64.4% for Sm³⁺. Equilibrium data were accurately described by the Langmuir isotherm model (R² > 0.974), indicating a dominant monolayer chemisorption mechanism. The maximum monolayer adsorption capacities (q_m) followed the order Dy(III) (189.59 ± 31.52 mg/g) > Sm(III) (162.27 ± 52.38 mg/g) > Nd(III) (139.90 ± 35.40 mg/g). The selectivity toward dysprosium was supported by distribution coefficients (Kd) and separation coefficients (β_Dy/Nd = 1.557 and β_Dy/Sm = 1.757 for the 6:0 system). FTIR analysis confirmed the direct coordination of lanthanide ions by sulfonic groups, as evidenced by the shifts in the νas(S=O) bands. SEM-EDX characterization revealed distinct post-sorption morphological changes (surface cracking and flaking) and confirmed significant REE accumulation on the resins (up to 4.04 wt.%) coupled with a stoichiometric decrease in sulfur content, validating the ion-exchange mechanism. These findings provide a deeper insight into the remote conformational effects governing interpolymer interactions and offer a highly promising approach for the selective recovery of REEs in hydrometallurgy.

This review outlines sustainable elastomers and green ingredients (derived from renewable resources) used in their formulation are summarized, analyzed, and discussed.

This study explores the potential for recycling natural rubber (NR) latex waste from balloon production through the devulcanization and revulcanization processes. The mechanical devulcanization of colored latex balloon waste was conducted, followed by revulcanization using a sulfur-based system. The reclaimed rubber’s properties, including crosslink density, tensile strength, and abrasion resistance, were compared with those of virgin NR. The results demonstrate that the reclaimed rubber maintains a crosslink density close to that of virgin NR. Hardness and abrasion resistance were comparable, indicating successful material recovery. Structural analyses, including FTIR and SEM microscopy, revealed that the devulcanization process effectively allowed for successful revulcanization. This study concludes that NR latex waste can be effectively recycled and reused in rubber composite formulations, offering a sustainable approach to waste management in the rubber industry and contributing to developing eco-friendly materials. In the context of this research, integrating advanced chemical and physical methods, such as solubility parameter calculations and enhanced devulcanization techniques, could further optimize the devulcanization process. These methods quantitatively enhance the efficiency of material recovery, offering a path to more sustainable recycling practices. The findings suggest that combining such advanced methodologies could significantly improve recycled NR latex’s overall performance and applicability in industrial applications.

Nanocomposites based on chlorobutyl rubber (CIIR) have been made using a variety of nanofillers such as carbon black (CB), nanoclay (NC), graphene oxide (GO), and carbon black/nanoclay hybrid filler systems. The hybrid combinations of CB/nanoclay are being employed in the research to examine the additive impacts on the final characteristics of nanocomposites. Atomic force microscopy (AFM), together with resistivity values and mechanical property measurements, have been used to characterise the structural composition of CIIR-based nanocomposites. AFM results indicate that the addition of nanoclay into CIIR increased the surface roughness of the material, which made the material more adhesive. The study found a significant decrease in resistivity in CIIR–nanoclay-based composites and hybrid compositions with nanoclay and CB. The higher resistivity in CB composites, compared to CB/nanoclay, suggests that nanoclay enhances the conductive network of carbon black. However, GO-incorporated composites failed to create conductive networks, which this may have been due to the agglomeration. The study also found that the modulus values at 100%, 200%, and 300% elongation are the highest for clay and CB/clay systems. The findings show that nanocomposites, particularly clay and clay/CB hybrid nanocomposites, may produce polymer nanocomposites with high electrical conductivity. Mechanical properties correlated well with the reinforcement provided by nanoclay. Hybrid nanocomposites with clay/CB had increased mechanical properties because of their enhanced compatibility and higher filler–rubber interaction. Nano-dispersed clay helps prevent fracture growth and enhances mechanical properties even more so than CB.

Microorganisms (MOs) are prominent in ecological functioning and balance. The rhizosphere is considered one of the most diverse ecosystems on Earth and serves as a breeding spot for many MOs. Rhizosphere microbial diversity changes according to plant species, genotype, and the nature of the soil. The current study reports the possible use of bacteria isolated from the rhizosphere of Azadirachta indica for synthesizing silver nanoparticles (AgNPs). The physicochemical characterization and antibacterial activity of these green synthesized AgNPs are also reported. The gene (16S rRNA) sequence of bacteria isolated from the rhizosphere showed a maximum similarity of 99.25% with Bacillus subtilis. After incubation, the colorless reaction mixture transformed to brown, which indicates the formation of AgNPs, and UV-vis spectral analysis also confirmed the biosynthesis of AgNPs. Compared to lower temperatures, the efficiency of AgNP synthesis was high at the higher temperature. The scanning electron microscope image demonstrated spherical-shaped AgNPs with sizes ranging from 18 to 21 nm. Energy-dispersive X-ray analysis established the elemental analysis of synthesized AgNPs. The synthesized AgNPs showed strong bactericidal properties against pathogenic bacteria Klebsiella pneumonia, Pseudomonas aeruginosa, Escherichia coli, and methicillin-resistant Staphylococcus aureus.

The growing demand for rare earth elements (REE) requires the search for economically viable materials to efficiently recover REE from various solutions. Our research aims to investigate the potential of using a combination of the ion exchangers Lewatit CNP LF (in H⁺ form) and AV-17-8 (in OH⁻ form) as an interpolymer system, “Lewatit CNP LF@AV-17-8” (X:Y), with varying mass ratios of X:Y to enhance the sorption efficiency of lutetium ions from nitrate solution. During the study, we used a range of analytical methodologies, including gravimetry, ultraviolet-visible (UV-VIS) spectroscopy, and inductively coupled plasma optical emission spectroscopy (ICP-OES). Our findings demonstrate that the interpolymer system “Lewatit CNP LF@AV-17-8” (X:Y), with a mass ratio of 4:2, exhibited a significantly enhanced sorption rate of Lu³⁺ ions (42%) compared to the individual Lewatit CNP LF (6:0) (25%) and the individual AV-17-8 (0:6) (21%) over a 48 h period. Moreover, this interpolymer system has demonstrated notable conformity to the Freundlich adsorption model, highlighting its performance as an effective sorbent for lutetium (III) ions. Notably, our study presents a novel utilization of the interpolymer system “Lewatit CNP LF@AV-17-8” (4:2), with an adsorption capacity of 221.05 mg/g, to enhance the recovery of lutetium ions. The research findings demonstrate its potential for enhancing the recovery of REE.