Zero-valent iron nanoparticles (nZVIs) are often used in environmental remediation. Their high surface area that is associated with their high reactivity makes them an excellent agent capable of transforming/degrading contaminants in soils and waters. Due to the recent development of green methods for the production of nZVIs, the use of this material became even more attractive. However, the knowledge of its capacity to de-grade distinct types of contaminants is still scarce. The present work describes the study of the application of green nZVIs to the remediation of soils contami-nated with a common antiinflammatory drug, ibuprofen. The main objectives of this work were to produce nZVIs using extracts of grape marc, black tea and vine leaves, to verify the degradation of ibuprofen in aque-ous solutions by the nZVIs, to study the remediation process of a sandy soil contaminated with ibuprofen using the nZVIs, and to compare the experiments with other common chemical oxidants. The produced nZVIs had nanometric sizes and were able to degrade ibuprofen (54 to 66% of the initial amount) in aqueous solutions. Similar remediation efficiencies were obtained in sandy soils. In this case the remediation could be enhanced (achieving degradation efficiencies above 95%) through the complemen-tation of the process with a catalyzed nZVI Fenton-like reaction. These results indicate that this remediation technology represents a good alternative to traditional and more aggressive technologies.

Additional treatment with NaOH of acid activated vermiculite results in even higher increase in the adsorption capacity in comparison to samples modified only in acidic solution (first step of activation) with respect to raw material. Optimization of treatment conditions and adsorption capacity for two cationic dyes (methylene blue (MB) and astrazon red (AR)), also as binary mixture, was evaluated. The capacity, based on column studies, increased from 48 ± 2 to 203 ± 4 mg g in the case of methylene blue and from 51 ± 1 to 127 ± 2 mg g in the case of astrazon red on starting and acid-base treated material, respectively. It was shown that adsorption mechanism changes for both cationic dyes after NaOH treatment and it results in decrease of adsorption rate. In binary mixtures methylene blue is bound stronger by adsorbent and astrazon red may be removed in initial stage of adsorption. Extensive studies on desorption/regeneration process proved high efficiency in recyclable use of all materials. Although cation exchange capacity decreases due to acid treatment, after base treatment exchange properties are used more efficiently. On the other hand, increased specific surface area has less significant contribution into the adsorption potential of studied materials. Obtained adsorbents worked efficiently in 7 adsorption-regeneration cycles and loss of adsorption capacity was observed only in two first cycles.

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Wet fine milling, as a pretreatment step to acid activation of vermiculite, was applied in order to decrease the environmental impact of the procedure commonly used to increase the mineral's adsorption capacity. Milling caused fragmentation of the material and several changes in its structure: edges of the flocks became frayed, the surface cracked, cation exchange capacity (CEC) increased, and most of the iron in oligonuclear and bulk form was removed. At the same time the specific surface area, crystallinity, chemical composition and adsorption capacity did not change significantly. Fine ground material was more susceptible to acid activation, which caused a decrease in the crystallinity and CEC, development of meso-and microporosity, an increase in the total volume of pores, in the specific surface and external surface areas. Micropores were developed faster in lower acid concentrations in the rough ground material, while the external surface area and total pores volume increased faster in the fine ground vermiculite. The latter material also had a higher CEC. Application of 0.5 mol L −1 HNO 3 to rough ground vermiculite did not change its adsorption capacity, however it changed from 55 ± 7 to 110 ± 8 mg g −1 when the material was fine ground. The optimal treatment conditions for both materials were obtained for 1.0 mol L −1 HNO 3 , however the adsorption capacity for the fine ground vermiculite increased more (i.e., from 55 ± 7 to 136 ± 7 mg g −1) than for its rough ground counterpart (i.e., 52 ± 7 to 93 ± 7 mg g −1). Concentrations higher than 1.0 mol L −1 resulted in deterioration of the adsorption capacities in both cases. Considering all the experimental outcomes, it can be concluded that the environmental impact of acid activation of vermiculite may be diminished by application of fine grinding of the material before the chemical activation process. Such treatment resulted in higher adsorption capacity at a given acid concentration compared to the rough ground material.

Hydrotalcite-like layered double hydroxide (LDH) materials were synthesized from liquid waste by-product produced during acid activation of vermiculite (raw (W) and expanded (Ve)), and by combining the waste with the activated mineral, novel hybrid vermiculitehydrotalcite-like materials were obtained in one-pot synthesis. Batch system adsorption experiments were performed on fresh and calcined (at 450 °C) materials using two anionic dyes (Congo Red-CR, and Reactive Red 184-R), a cationic dye (Astrazon Red-AR), and Cu2+. Calcination significantly increased the materials' adsorption capacities for all the pollutants. The highest adsorption capacities

Thermal treatment of hydrotalcite at increasing temperatures resulted in formation of mixed oxides that exhibited different adsorption behavior toward anionic and cationic industrial dyes. The material annealed at 450 ○ C was characterized by the highest maximum adsorption capacity for both types of dyes. The adsorption was strongly pH dependent and for the anionic dye abatement low pH was favored whilst higher pH was more preferable for removal of the cationic dye. According to the equilibrium experiments, the maximum adsorption capacity increased from 179 ± 5 to 291 ± 8 mg g -1 in case of the anionic dye at pH 3.5 and from 6 ± 2 to 48 ± 2 mg g -1 in case of the cationic dye at pH 8.0, on starting and thermally treated material at 450 ○ C, respectively. Detailed characteristics of spent adsorbent and its reconstructed form revealed that after each cycle of adsorption and thermal regeneration the maximum adsorption capacity of the material decreased due to changes in the structure and accumulation of sulfur compounds. Evolution of specific surface area and porosity was correlated with annealing temperatures and behavior of dye's residues.