Silica−Polyamine-Based Carbon Composite Adsorbents as Media for Effective Hydrogen Sulfide Adsorption/Oxidation

Abstract

New silica-carbon adsorbents were prepared by pyrolysis of silica-polyamine composites at 600 °C. The heat treatment was expected to activate nitrogen for effective hydrogen sulfide oxidation. Moreover, the same pyrolysis treatment was applied on silica-polyamine adsorbents previously used to remove copper ions for aqueous solution. The performance of these materials as H 2 S adsorbents was tested using a home-developed dynamic breakthrough test. Samples from before and after the adsorption process were characterized by adsorption of nitrogen, surface pH, thermal analysis, elemental analysis, FTIR, optical microscopy, and solid-state CPMAS 13 C NMR. Differences in the performance were linked to the surface properties such as content of nitrogen, content of copper, surface acidity/basicity, and porous structure. It was found that the capacity for hydrogen sulfide removal/selectivity for oxidation to sulfur depends on the granulation of the silica matrix, the kind of polymer used for grafting, surface basicity, and porosity. Thermal transformation of the polymer causes the formation of new highly dispersed catalytic centers with active nitrogen atoms. The silica matrix also provides pore space for the storage of oxidation products, mainly elemental sulfur.

A methods study of immobilization of PONOP pincer transition metal complexes on silica polyamine composites (SPC)

“…[42] These studies required thermal stability of the SPCs and this has been confirmed by DTG analysis. [43] In addition, a series of luminescent ruthenium complexes with various types of ligands have also been successfully immobilized on SPC. [14] Given the ease of modification of the SPC amine surface with aromatic ligands using the Mannich Reaction without prior parasubstitution, [38,44] and its ability to provide a basic surface for bifunctional catalysis, SPC would appear to be a suitable candidate for the immobilization of metal pincer complexes.…”

Investigations on the surface structure and properties of silica‐polyamine composites on the nanoscales and microscales

“…Our initial investigations began in the early 1990's and focused on developing a metal remediation technology that was capable of being commercialized using the SPC platform. Eventually, this surface was expanded to a wider range of applications and synthetic approaches . The early years focused on the synthesis and applications of the polyamine‐amorphous silica gel composites to problems in heavy metal ion removal and recovery .…”

“…The early years focused on the synthesis and applications of the polyamine‐amorphous silica gel composites to problems in heavy metal ion removal and recovery . Later characterization of the polymer‐surface interface and refining the use of polymer modifying ligands to improve metal selectivity was the focus of the research . Most recently, the emphasis has been on the synthesis of these composites by more environmentally benign routes, the development of materials that can capture anions as well as cations and to their applications in catalysis .…”

Efficient removal of boron acid by N-methyl-d-glucamine functionalized silica–polyallylamine composites and its adsorption mechanism

“…Furthermore, the elastic nature of polymer matrices limits their use in packed column systems, because the frequent swings between shrinking and swelling during the adsorptionregeneration cycles can lead to a short lifetime and increase the requirement of dead volume in plant design. Recently, the Rosenberg Group reported the synthesis of hydrophilic silica-polyallylamine composites (SPC) and their application for removing toxic metal cations, such as Cu 2+ and Ni 2+ [7][8][9]. The use of SPC as adsorbent matrices for the removal of hazardous anions and non-ions, however, has not been explored.…”