Rice Husk Ash-Derived MCM-22 as a Multifunctional Catalyst and Adsorbent for Chalcone Synthesis and CO₂ Adsorption

Abstract

Agricultural residues that contain concentrated silica provide an attractive route to functional inorganic materials while reducing dependence on conventional silica precursors. Here, a rice-husk-ash-derived MCM-22 zeolite is proposed as a bifunctional material for catalytic chalcone synthesis and carbon-dioxide capture. Rice husk ash was converted into a silica-rich precursor and incorporated into an aluminosilicate gel followed by hydrothermal crystallization. The resulting material was evaluated using powder X-ray diffraction, Fourier-transform infrared spectroscopy, nitrogen physisorption, electron microscopy, energy-dispersive X-ray spectroscopy, temperature-programmed desorption, thermogravimetry, X-ray photoelectron spectroscopy and solid-state 29Si MAS NMR. An illustrative dataset gives characteristic MWW reflections, a BET surface area of 312 m² g⁻¹, a micropore/mesopore contribution and an Si/Al ratio near 18. The catalyst promoted the condensation of benzaldehyde with acetophenone to form chalcone, reaching a model isolated yield of 91.4% under optimized conditions. The same solid exhibited a model CO₂ uptake of 2.55 mmol g⁻¹ at 298 K and 1 bar. The dual functionality is attributed to the combination of framework acidity, high external surface area, microporous adsorption sites and oxygen-containing surface groups. The study demonstrates a potentially circular route from rice-processing waste to a value-added catalytic and carbon-capture material; however, the reported numerical values are intended as a manuscript-development dataset rather than evidence of completed experiments.