Multi-simultaneous Absorption and Adsorption Processes for Biogas Purification using Ca(OH)2 Solution and Activated Clinoptilolite Zeolite/Chitosan Composites

Abstract

This study examined the effects of acid/base activation and chitosan coating on clinoptilolite zeolite as an adsorbent for biogas purification from palm oil mill effluent (POME) using simultaneous absorption-adsorption methods. The effects of chitosan concentration in the clinoptilolite zeolite/chitosan (ZAC) composites were studied to determine the best type of adsorbent for purifying biogas to obtain the highest methane (CH4) concentration: the biogas produced from POME via an anaerobic digestion process had a CH4 concentration of 87% and a carbon dioxide (CO2) concentration of 13%. In this study, the Ca(OH)2 solution was used for the absorption process, and the ZAC composite was used as the adsorbent in the adsorption process. To enhance the adsorption efficiency of the adsorbent when purifying biogas, clinoptilolite zeolite (ZA) was activated using strong acid (HCl) and base (NaOH) in various concentrations (ranging from 1-3 M), calcination at 450°C for 2 h, and coating with chitosan concentrations (ranging from 0.25-1 v/v%). The ZA was coated with chitosan to increase its adsorption efficiency, as chitosan contains high levels of amine and hydroxyl groups that interact with CO2 impurities and form carbamic acid, ultimately producing carbamate salt. The composition of biogas before and after treatment was analyzed using gas chromatography. Overall, the final content of the biogas after the purification process with absorption using the Ca(OH)2 solution and adsorption in a fixed-bed column using the ZAC2-0.5 composite was 0.42% CO2 and 99.58% CH4. The purified biogas had a very high methane gas content; thus, this study's findings suggest that purified biogas can be used as a clean energy source for wider industrial applications.

The Effect of Various Zeolites as an Adsorbent for Bioethanol Purification using a Fixed Bed Adsorption Column

“…Not all zeolites have the ability to adsorb water; it depends on their Si/Al ratio and the type of cation contained in their aluminosilicate bond (Kulprathipanja, 2010). Based on the research, zeolites with a lower Si/Al ratio tend to be hydrophilic, while zeolites with a higher Si/Al ratio tend to be hydrophobic (Kusrini et al, 2019). The Si/Al ratios in zeolites that have hydrophilic properties ranges from low to medium.…”

Micro-structured Materials for the Removal of Heavy Metals using a Natural Polymer Composite

“…Adsorption isotherm data were analysed by the Langmuir isotherm model that accounts for monolayer surface adsorption (Kusrini et al, 2019a;Kusrini et al, 2019b). The Langmuir isotherm model, Qe, was fitted using a linearized form, according to Equation 1.…”

“…In recent years, adsorption-based methods have been employed to investigate the removal of heavy metal ions from wastewater (Gupta et al, 2012;Salah et al, 2014;Zhang et al, 2018;Vieira et al, 2019;Kusrini et al, 2020a;Kusrini et al, 2020b). Adsorption is typically employed in industries due to its high efficiency and cost-effectiveness (Kusrini et al, 2019a;Kusrini et al, 2019b;Kusrini et al, 2019c). Some polymers and synthetic materials, such as chitosan (CHN), hydroxyapatite (HAP), activated carbon and zeolites have been reportedly used as adsorbents to remove heavy metal ions from aqueous media (Gupta et al 2012;Salah et al, 2014;Zhang et al, 2018;Vieira et al, 2019).…”

“…A CHN/HAP composite nanofiber membrane for the adsorption of Pb, Co and Ni ions from an aqueous solution has been reported (Aliabadi et al, 2014). The presence of amine (-NH2) and hydroxyl (-OH) groups in CHN can serve as active sites for the removal of heavy metals from aqueous media via adsorption (Gupta et al 2012;Aliabadi et al, 2014;Kusrini et al, 2019a). Chromium (Cr) is well known to be the main additive in stainless steel that inhibits corrosion.…”

Immobilization of Cholesterol Oxidase in Chitosan Magnetite Material for Biosensor Application

“…Chitosan is a biopolymer with a number of advantages; it is renewable, nontoxic, and highly available in Nature (Peter, 1995). In industrial applications, chitosan is a source for composites of activated clinoptilote zeolite/chitosan used as a support for biogas purification (Kusrini et al, 2019). According to Ahmad and Goswami (2014), chitosan also can be used as a support for bioreactions.…”