Browsing by Author "Torrecilla-Soria, J."
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Item Highly concentrated cationic flocculants based on 80/20 wt % [2-(acryloyloxy)ethyl]trimethylammonium chloride/acrylamide in an inverse microemulsion: Influence of the copolymerization variables on the flocculation performance(2009-12-01) Ochoa-Gómez, José R.; Nieto-Mestre, J.; Escudero-Sanz, Francisco J.; Sasia, P. M.; Río, F.; Torrecilla-Soria, J.; Katime, Issa A.; VALORIZACIÓN DE RESIDUOS; ECONOMÍA CIRCULAR; SGThe influence of the total comonomer concentration (TCC; 30-42 wt %), emulsifier concentration (EC; 7.3-23 wt %), hydrophilic-lipophilic balance (HLB; 9-9.9), crosslinking agent (N,N'-methylene bisacrylamide) concentration (CAC; 0-122.8 ppm with respect to TCC), and isopropyl alcohol (chain-transfer agent) concentration (IPC; 0-1.5 wt % with respect to TCC) on the flocculation performance (FP) of 80/20 wt % acrylamide (AM)/[2-(acryloyloxy)ethyl] trimethylammonium chloride (ADQUAT) copolymers obtained by semicontinuous inverse microemulsion copolymerization was studied with capillary suction time testing for FP assessment on anaerobic digested sludges. FP increased as TCC decreased, was nearly unaffected by EC, was maximum with an HLB of 9.5, decreased strongly with CAC, and showed a peak value with an IPC of 1 wt %. At a very high TCC, copolymer growth in a highly collapsed state resulted in greatly structured, high weight-average molar mass flocculants with decreased swelling capacities (SCs), which did not favor bridging flocculation, and in increased shielding of their positive charges, which did not favor charge neutralization flocculation. However, industrially needed latices with both high TCC and good FP could be obtained by the addition of isopropyl alcohol, which, below a concentration of 1 wt %, improved FP by decreasing the weight-average molar mass and thereby enhancing SC while maintaining long enough chains to be effective for bridging flocculation. On the basis of the results, new star-shaped ADQUAT/AM copolymers are envisioned as flocculants with superior FP. A synthetic route is proposed.Item Purification and upgrading of biogas by pressure swing adsorption on synthetic and natural zeolites(2010-10) Alonso-Vicario, A.; Ochoa-Gómez, José R.; Gil-Río, S.; Gómez-Jiménez-Aberasturi, O.; Ramírez-López, C. A.; Torrecilla-Soria, J.; Domínguez, A.; Laboratorio Químico; BIOECONOMÍA Y CO2; SGThe cleaning (H2S removal) and upgrading (CO2/CH4 ratio adjustment for syngas synthesis) of biogas by pressure swing adsorption (PSA) with thermal desorption using two synthetic molecular sieves (5A and 13X) and a natural zeolite (Clinoptilolite) as adsorbent materials have been studied. Prior to use, zeolites were activated according to literature methods and supplier recommendations in order to dispose of adsorbed gases and soluble impurities which may compete with H2S and CO2 for the active sites of the zeolites. The behaviours of the zeolites have been compared by using three basic parameters: selectivity, capacity and regenerability. The experimental results indicate that Clinoptilolite is the best material choice because it is simultaneously suitable both for the purification and upgrading of biogas. For a CH4/CO2/H2S biogas molar composition of 59.95/39.95/0.10, the breakthrough capacity of Clinoptilolite at 1cm/s biogas feeding velocity, 7bar and 25°C is 1.39mgH2S/g Clinoptilolite, twice the adsorption capacity of the synthetic molecular sieves subjected to study. The high CO2 adsorption capacity observed (173.9mg CO2/g Clinoptilolite) makes the adjusting of CH4/CO2 ratio in the biogas possible. Additionally, Clinoptilolite is completely regenerable and stable through several adsorption-desorption cycles which, together with its abundance and low cost, make this process highly attractive from an economical standpoint. Finally, this study demonstrates the importance of the selection of the optimal activation method of natural zeolites in order to offset variable composition and low purity often responsible for poorer separation performance compared to synthetic zeolites.