Fabrication of an efficient ZIF-8 alginate composite hydrogel material and its application for enhanced copper (II) adsorption from aqueous solutions

A novel zeolitic imidazolate framework-8 (ZIF-8) alginate composite hydrogel material (PVA/SA@ZIF-8) is alginate composite bead which was fabricated by grafting ZIF-8 on the surface of the sodium alginate hydrogel beads...

Naturally Derived a-Tricalcium Phosphate Based Porous Composite Bead Production

In this study, a simple, innovative approach is applied to produce porous a-TCP-CeO2-Al2O3 composite beads via using bovine bone-derived hydroxyapatite, cerium oxide, and alumina ceramics. Bovine-bone derived hydroxyapatite was obtained via calcination of bones at 950°C for 3 hours. Hydroxyapatite is a thermally unstable biomaterial at high temperatures, and depending on its stoichiometry decomposes at 800-1200°C. Sodium alginate was successfully used as an in situ gelling templates for the production of the ceramic beads and starch, an environmentally friendly and economic pore-forming agent, is used to achieve interconnected, highly open porosity containing composite beads. Sintering of the ceramic−starch−alginate green composite beads at 1200°C for 1 hour resulted in the decomposition of the hydroxyapatite phase and formation of a-TCP. XRD analysis revealed that a-TCP-CeO2-Al2O3 composite beads were achieved. XRD analysis confirmed the formation of a-TCP phase in all composite compositions. SEM investigations of the produced composite beads revealed that bimodal pore size distribution, fine and coarse, was achieved.

Adsorption of Pb2+ ions from aqueous solutions by gelatin/activated carbon composite bead form

Gelatin and activated carbon materials have been combined together to obtain a gelatin/activated carbon composite bead form which is ecofriendly, nontoxic, biocompatible, and inexpensive material. In this paper, gelatin/activated carbon adsorption for Pb2+ ions from aqueous solutions was studied experimentally under various conditions. The experimental conditions such as contact time, solution pH, and gelatin/activated carbon dosage were examined and evaluated by using batch adsorption experiments. The maximum adsorption capacity of gelatin/activated carbon for Pb2+ ions was obtained to be 370.37 mg g−1. This maximum capacity was comparable with that of commercial ion exchange resins and it was much higher than those of natural zeolites. The uptake process for Pb2+ ions was found to be relatively fast with 92.15% of the adsorption completed in about 5 min in batch conditions. The adsorption capacity was also strongly solution pH dependent. Adsorption was observed at pH value as low as 2.0 and maximum adsorption was achieved at a pH of approximately 5. The results indicated that the gelatin/activated carbon was effective to be used as an adsorbent for Pb2+ ions removal in wastewater treatment.