Disclosed are silica bound zeolite adsorbent particles which possess high volumetric gas adsorption capacity for the adsorption and/or desorption of gases. The adsorbent are highly effective as a gas source in volumetrically constrained applications. The silica-bound zeolite adsorbents possess a relatively high zeolite content simultaneously with a relatively low intra-particle pore volume as compared to the clay bound zeolite aggregates heretofore used as a gas source in volumetrically constrained environments, e.g. instant beverage carbonation processes, devices or systems.