Abstract
Calcium is one of the divalent ions contributing to the hardness level of the water. This work describes the removal of calcium ions from aqueous solution using carbonate salts as precipitants and the recovery of homogeneous calcium carbonate crystals via a fluidized-bed homogeneous crystallization (FBHC) process without a heterogeneous seed material. The considered parameters were effluent pH, initial molar ratio of carbonate salt to Ca, up-flow velocity, and cross-section loading. The removal efficiency of Ca hardness reached 95% at the optimal pH of 10–11 and the corresponding crystallization ratio was 88% for initial concentrations of Ca of 50–330 ppm. The FBHC process was effective with a cross-section loading of calcium in the water of up to 4.5 kg/m2/h. The efficiency of Ca immobilization as the crystal grew on the fluidized pellets was greatly improved by adjusting the degree of supersaturation in the range 2–3, resulting in the crystallization ratio (CR) and total removal of Ca (TR) of 88% and 92%, respectively. XRD analysis revealed that the formed crystals comprised two calcium carbonate (CaCO3) phases—calcite and aragonite. SEM images of the surface morphology revealed that calcium carbonate particles (around 1–2 mm) were formed by the aggregation of fine crystals (around 5 µm).
| Original language | English |
|---|---|
| Pages (from-to) | 378-385 |
| Number of pages | 8 |
| Journal | Journal of the Taiwan Institute of Chemical Engineers |
| Volume | 78 |
| DOIs | |
| Publication status | Published - 2017 Sep 1 |
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All Science Journal Classification (ASJC) codes
- Chemistry(all)
- Chemical Engineering(all)
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Removal of calcium hardness from solution by fluidized-bed homogeneous crystallization (FBHC) process. / Mahasti, Nicolaus N.N.; Shih, Yu Jen; Vu, Xuan Tung; Huang, Yao-Hui.
In: Journal of the Taiwan Institute of Chemical Engineers, Vol. 78, 01.09.2017, p. 378-385.Research output: Contribution to journal › Article
TY - JOUR
T1 - Removal of calcium hardness from solution by fluidized-bed homogeneous crystallization (FBHC) process
AU - Mahasti, Nicolaus N.N.
AU - Shih, Yu Jen
AU - Vu, Xuan Tung
AU - Huang, Yao-Hui
PY - 2017/9/1
Y1 - 2017/9/1
N2 - Calcium is one of the divalent ions contributing to the hardness level of the water. This work describes the removal of calcium ions from aqueous solution using carbonate salts as precipitants and the recovery of homogeneous calcium carbonate crystals via a fluidized-bed homogeneous crystallization (FBHC) process without a heterogeneous seed material. The considered parameters were effluent pH, initial molar ratio of carbonate salt to Ca, up-flow velocity, and cross-section loading. The removal efficiency of Ca hardness reached 95% at the optimal pH of 10–11 and the corresponding crystallization ratio was 88% for initial concentrations of Ca of 50–330 ppm. The FBHC process was effective with a cross-section loading of calcium in the water of up to 4.5 kg/m2/h. The efficiency of Ca immobilization as the crystal grew on the fluidized pellets was greatly improved by adjusting the degree of supersaturation in the range 2–3, resulting in the crystallization ratio (CR) and total removal of Ca (TR) of 88% and 92%, respectively. XRD analysis revealed that the formed crystals comprised two calcium carbonate (CaCO3) phases—calcite and aragonite. SEM images of the surface morphology revealed that calcium carbonate particles (around 1–2 mm) were formed by the aggregation of fine crystals (around 5 µm).
AB - Calcium is one of the divalent ions contributing to the hardness level of the water. This work describes the removal of calcium ions from aqueous solution using carbonate salts as precipitants and the recovery of homogeneous calcium carbonate crystals via a fluidized-bed homogeneous crystallization (FBHC) process without a heterogeneous seed material. The considered parameters were effluent pH, initial molar ratio of carbonate salt to Ca, up-flow velocity, and cross-section loading. The removal efficiency of Ca hardness reached 95% at the optimal pH of 10–11 and the corresponding crystallization ratio was 88% for initial concentrations of Ca of 50–330 ppm. The FBHC process was effective with a cross-section loading of calcium in the water of up to 4.5 kg/m2/h. The efficiency of Ca immobilization as the crystal grew on the fluidized pellets was greatly improved by adjusting the degree of supersaturation in the range 2–3, resulting in the crystallization ratio (CR) and total removal of Ca (TR) of 88% and 92%, respectively. XRD analysis revealed that the formed crystals comprised two calcium carbonate (CaCO3) phases—calcite and aragonite. SEM images of the surface morphology revealed that calcium carbonate particles (around 1–2 mm) were formed by the aggregation of fine crystals (around 5 µm).
UR - http://www.scopus.com/inward/record.url?scp=85023603501&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85023603501&partnerID=8YFLogxK
U2 - 10.1016/j.jtice.2017.06.040
DO - 10.1016/j.jtice.2017.06.040
M3 - Article
AN - SCOPUS:85023603501
VL - 78
SP - 378
EP - 385
JO - Journal of the Taiwan Institute of Chemical Engineers
JF - Journal of the Taiwan Institute of Chemical Engineers
SN - 1876-1070
ER -