Mineral-based Architectures Group
About the lab
Our research activities are devoted to the use of natural and synthetic minerals and mineral resources for the production of functional materials with applications in industry and for environment protection.
Featured projects (1)
More information: http://www.mba.agh.edu.pl/?page_id=550
Featured research (45)
Layered double hydroxides (LDH) are promising materials with applications in industry, including wastewater treatment. Consequently, great emphasis is placed on developing methods to obtain those materials at the lowest possible cost. This work investigated using magnesite, dolomite, halloysite/kaolinite and hematite as substrates for the synthesis of LDH-containing materials. All the obtained materials were characterized by XRD, FTIR, SEM and chemical analysis. Their specific surface area and zeta potential were determined. The results showed, that pre-treatment of raw mineral precursors is unnecessary for efficient extraction of metal ions. The co-precipitation synthesis parameters were reduced to ageing at room temperature for a short period of time (2 h) leading to a successful formation of LDH in all samples. Depending on the used substrates, the materials showed minor differences in structural properties. However, despite that, all the materials exhibited a very high affinity towards As(V) (645.2–1483.2 mmol/kg). Therefore the described synthesis approach is promising in terms of future large-scale applications of LDH in wastewater treatment.
In this study, two-step surface modification of sawdust using triethanolamine (at 180 °C) and iodomethane (at 42 °C) was performed to produce a novel quaternized biosorbent, TEA-I-SD. The characterization studies revealed significant morphological changes in the sawdust and successful quaternization with a nitrogen content of 5.75%. The highest vanadium removal (96.2%) was achieved at pH 4 (dosage 1 g/L, initial vanadium concentration 19.1 mg/L). Equilibrium was achieved within eight hours of contact time and the adsorption kinetics were well fitted with the pseudo-second-order model. Both film diffusion and intra-particle diffusion contributed to the adsorption process, while the latter was the rate-limiting step. The maximum vanadium adsorption capacity of TEA-I-SD (35.0 mg/g, pH 4) was close to the theoretical value obtained from the Langmuir model. The best fit was achieved with the Redlich-Peterson model, exhibiting a monolayer adsorption phenomenon. Tests with real mine water containing 11 mg/L of vanadium also confirmed its high removal (91.3%, dosage 1 g/L) using TEA-I-SD at pH 4. The TEA-I-SD could be reused three times without significant capacity loss after regeneration, although the desorption efficiency was rather low (synthetic solution: 38.5-40.5% and mine water: 26.2-43.1%).
Multiple attempts have been made to lower the cost of the adsorbents for the wastewater treatment. This work investigated the possibility of obtaining Mg/Al and Mg/Fe LDH without excessive use of chemical reagents, by replacing them with cheaper substrates. Magnesite and dolomite were used as Mg-sources in a facile co-precipitation synthesis at room temperature. Several variants of LDHs were studied regarding their chemical composition, M II /M III molar ratio and the synthesis time. Their comprehensive characterization was provided and compared to the reference materials obtained from chemical reagents. Depending on the molar ratio the reference samples exhibited a clear shift of the XRD basal reflections, and different species of interlayer car-bonates were identified by spectroscopic methods. The LDHs derived from minerals had similar structural features as compared to the reference samples. However, the synthesis of mineral-based LDHs resulted in the formation of additional phases. The formation of LDH from minerals with a molar ratio higher than 2:1 was impossible in the applied conditions. The 2 h ageing time was enough to enable the LDH formation. The transformation procedure of magnesite and dolomite to LDH via simplified synthesis procedure may significantly reduce the final cost of the adsorbents by excluding expensive chemical reagents.
Mycotoxins in feed and food are highly toxic and pose a serious danger even at very low concentrations. The use of bentonites in animal diet can reduce toxin bioavailability. However, some mycotoxins like fumonisin B1 (FB1) form anionic species which excludes the use of negatively charged clays. Layered double hydroxides (LDH) with anion-exchange properties, in theory, can be perfect candidates to adsorb FB1. However, fundamental research on the use of LDH for mycotoxins removal is scarce and incomplete. Thus, the presented study was designed to explore such a possibility. The LDH materials with differing chemistry and layer charge were synthesized by co-precipitation both from metal nitrates and chlorides and were then tested for FB1 removal. XRD, FTIR, XPS, and chemical analysis were used for the LDH characterization and to obtain insight into the removal mechanisms. A higher adsorption capacity was observed for the Mg/Al LDH samples (~0.08–0.15 mol/kg) in comparison to the Mg/Fe LDH samples (~0.05–0.09 mol/kg) with no difference in removal efficiency between Cl and NO3 intercalated LDH. The adsorption capacity increased along with lower layer charge of Mg/Al and was attributed to the lower content of bonded carbonates and the increase of non-polar sites which led to matching between the adsorption domains of LDH with FB1. The FTIR analysis confirmed the negative effect of carbonates which hampered the adsorption at pH 7 and led to the highest adsorption at pH 5 (FB1 content ~15.8 ± 0.75 wt.%). The fast surface adsorption (1–2 min) was dominant and XRD analysis of the basal spacing indicated that no FB1 intercalation occurred in the LDH. The XPS confirmed a strong interaction of FB1 with Mg sites of LDH at pH 5 where the interaction with FB1 carboxylate moieties COO− was confirmed. The research confirmed a high affinity and selectivity of LDH structures towards anionic forms of FB1 mycotoxin.