Experimental Study of CO₂ Mineralization in Ca²⁺-Rich Aqueous Solutions Using Tributylamine as an Enhancing Medium

Abstract

The feasibility of using tributylamine as a pH regulator to enhance CO 2 mineralization in Ca 2+ -rich aqueous solutions was demonstrated. The influencing factors, such as the makeup of the extraction system and the operating parameters, were investigated experimentally. With N-butyl alcohol as the diluent of tributylamine, the mineralization ratio could reach approximately 93% for an initial concentration of 3.4 g/L when the dilution ratio was 2:1 and the ratio of organic to water was 4:1. A stirring speed of 500 rpm was observed to be sufficient to ensure good mixing of organic and water phases. A rise in the reaction temperature results in a lowering of the mineralization ratio. Characterization using X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated that the precipitation product is pure CaCO 3 that is sufficiently good for use in commercial filling agents. Moreover, it was determined that Ca(OH) 2 powder acted as an excellent regenerant to turn N(C 4 H 9 ) 3 · H + in the organic phase back into tributylamine. The extraction system exhibited stable performance for acting as the enhancing medium for CO 2 mineralization reactions in Ca 2+ -rich aqueous solutions, after 11 rounds of regeneration cycles. The results of this study provide information that is relevant for practical application of this CO 2 fixation concept.

Bio-mineralisation, characterization, and stability of calcium carbonate containing organic matter

“…The centrifugal supernatant Ca 2+ concentration was measured by AAS. Ignoring the Ca 2+ utilised by the strain, most of the Ca 2+ would be converted to CaCO 3 , and then the Ca 2+ biomineralisation efficiency was calculated by use of eqn (1) : 38 where C 1 and C 2 are the initial, and end (after shaking-culturing for 7 days) concentrations of Ca 2+ (mg L −1 ), respectively.…”

Experiment and Optimization for Simultaneous Carbonation of Ca2+ and Mg2+ in A Two-phase System of Insoluble Diisobutylamine and Aqueous Solution

“…The volume ratio of organic and aqueous phases, i.e. phase ratio, was proved to affect the carbonation performance greatly in our previous experiments 21 , so the effect of phase ratio was also investigated here. Figure 5 shows the percentages of precipitation of Ca 2+ and Mg 2+ at different phase ratios.…”

Insight into thermal dissociation of tri‐n‐octylamine hydrochloride: The key to realizing CO2 mineralization with waste calcium/magnesium chloride liquids

“…Among the various CCS methods, mineralization by converting CO 2 to carbonate minerals offers an attractive approach for the safe storage and effective utilization of CO 2 . Some Mg 2+ /Ca 2+ —rich aqueous resources, such as seawater, salt lake brines, and industrial effluents have potential application in mineralization of CO 2 .…”

“…Apart from the coupled process of CaCl 2 , the extraction technology for the production of compound fertilizers such as potassium dihydrogen phosphate (KH 2 PO 4 ) [11][12][13] could also generate amine hydrochloride which is shown in Equation (2). The efficient regeneration of amine extractant is also a key point.…”