New hybrid clay adsorbent based on kaolinite clay and Carica papaya seeds with improved cation exchange capacity (CEC), rate of heavy metal ion uptake, and adsorption capacity for heavy metal ions were prepared. The CEC of the new material is ca. 75 meq/100 g in spite of the unexpectedly low surface area (≈9 m 2 /g). Accordingly, the average particle size of the hybrid clay adsorbent decreased from over 200 to 100 μm. The hybrid clay adsorbent is a highly efficient adsorbent for heavy metals. With an initial metal concentration of 1 mg/L, the hybrid clay adsorbent reduces the Cd 2+ , Ni 2+ , and Pb 2+ concentration in aqueous solution to ≤4, ≤7, and ≤20 μg/L, respectively, from the first minute to over 300 min using a fixed bed containing 2 g of adsorbent and a flow rate of ≈7 mL/min. These values are (with the exception of Pb 2+ ) in line with the WHO permissible limits for heavy metal ions. In a cocktail solution of Cd 2+ , and Ni 2+ , the hybrid clay shows a reduced rate of uptake but an increased adsorption capacity. The CEC data suggest that the adsorption of Pb 2+ , Cd 2+ , and Ni 2+ on the hybrid clay adsorbent is essentially due to ion exchange. This hybrid clay adsorbent is prepared from materials that are abundant and by a simple means that is sustainable, easily recovered from aqueous solution, nonbiodegradable (unlike numerous biosorbent), and easily regenerated and is a highly efficient alternative to activated carbon for water treatment.

There is a demand for new and robust PdII extractants due to growing recycling rates. Chelating dithioethers are promising substances for solvent extraction as they form stable square‐planar complexes with PdII. We have modified unsaturated dithioethers, which are known to coordinate PdII, and adapted them to the requirements of industrial practice. The ligands are analogues of 1,2‐dithioethene with varying electron‐withdrawing backbones and polar end‐groups. The crystal structures of several ligands and their palladium complexes were determined as well as their electro‐ and photochemical properties, complex stability and behaviour in solution. Solvent extraction experiments showed the superiority of some of our ligands over conventionally used extractants in terms of their very fast reaction rates. With highly selective 1,2‐bis(2‐methoxyethylthio)benzene (4) it is possible to extract PdII from a highly acidic medium in the presence of other base and palladium‐group metals.

Fifteen N-butylpyridinium salts -five monometallic [C 4 Py] 2 [MBr 4 ] and ten bimetallic [C 4 Py] 2 [M 0.5 a M 0.5 bBr 4 ] (M=Co, Cu, Mn, Ni, Zn) -were synthesized, and their structures and thermal and electrochemical properties were studied. All the compounds are ionic liquids (ILs) with melting points between 64 and 101 °C. Powder and single-crystal X-ray diffraction show that all ILs are isostructural. The electrochemical stability windows of the ILs are between 2 and 3 V.The conductivities at room temperature are between 10 À 5 and 10 À 6 S cm À 1 . At elevated temperatures, the conductivities reach up to 10 À 4 S cm À 1 at 70 °C. The structures and properties of the current bromide-based ILs were also compared with those of previous examples using chloride ligands, which illustrated differences and similarities between the two groups of ILs.

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Eight d-metal-containing N-butylpyridinium-based ionic liquids (ILs) were synthesized, characterized, and investigated for their optical properties.