TY - JOUR
T1 - Adsorption characteristics of arsenate on colloidal nanosheets of layered double hydroxide
AU - Koilraj, Paulmanickam
AU - Takaki, Yu
AU - Sasaki, Keiko
N1 - Funding Information:
This work is financially supported by Grand-in-Aid for Scientific Research through 15F15380 and 16H02435 from Japan Society for the Promotion of Science (JSPS) and “Progress 100” (World Premier International Researcher Invitation Program of Kyushu University) , which is funded using the special expenses for fiscal 2014 (for enhancing the functions of national universities) provided by the operating expense grants of the Ministry of Education, Culture, Sports, Science and Technology (MEXT). TEM observation was conducted at the Research Laboratory for high Voltage Electron Microscopy (HVEM), Kyushu University with assist by Ms. Midori Muta.
Publisher Copyright:
© 2016 Elsevier B.V.
PY - 2016/12/1
Y1 - 2016/12/1
N2 - Nanomaterials have gained much interest in water remediation and pollution control in recent years. However, the toxicity associated with nanoparticles remaining in solution after remediation has high impact on the environment. The present study examined the synthesis and characterization of colloidal Mg2Al-NO3 layered double hydroxide (Mg2Al-UD-LDH) nanosheets and their application as adsorbent toward arsenate immobilization. Colloidal LDH nanosheets featured the absence of nanoparticles release in the environment differently from other nanomaterials. The adsorption studies conducted in batch method, revealed that colloidal Mg2Al-UD-LDH nanosheets (obtained by ultrasonic treatment of Mg2Al-NO3-LDH suspension) achieved a higher arsenate adsorption density of 1.21 mmol/g than parent Mg2Al-NO3-LDH (1.16 mmol/g) at a solid-to-solution dosage of 0.78 g LDH/L. The adsorption mechanism of arsenate onto colloidal Mg2Al-UD-LDH nanosheets proceeded through restacking of the nanosheets, besides ion-exchange onto Mg2Al-NO3-LDH and surface adsorption onto Mg2Al-CO3-LDH. Kinetics of arsenate adsorption onto colloidal Mg2Al-UD-LDH nanosheets was rapid, reaching equilibrium within 5 min, whereas equilibrium was reached within 120 min in the presence of Mg2Al-NO3-LDH. The colloidal LDH nanosheets stacking effect was restricted at higher LDH/As ratios owing to electrostatic repulsion among the nanosheets, as determined by zeta potential measurements. Semi-pilot scale static model systems for arsenate adsorption were examined to further investigate the adsorption performance of colloidal Mg2Al-UD-LDH nanosheets in natural water systems such as river, pond, or lake. Arsenate adsorption was rapid onto colloidal Mg2Al-UD-LDH nanosheets owing to their high dispersibility; specifically, 100% adsorption efficiency was achieved within 5 min. Thus, the high adsorption capacity, dispersibility, and fast kinetics of arsenate removal onto colloidal Mg2Al-UD-LDH nanosheets promising for use as an efficient adsorbent for water remediation.
AB - Nanomaterials have gained much interest in water remediation and pollution control in recent years. However, the toxicity associated with nanoparticles remaining in solution after remediation has high impact on the environment. The present study examined the synthesis and characterization of colloidal Mg2Al-NO3 layered double hydroxide (Mg2Al-UD-LDH) nanosheets and their application as adsorbent toward arsenate immobilization. Colloidal LDH nanosheets featured the absence of nanoparticles release in the environment differently from other nanomaterials. The adsorption studies conducted in batch method, revealed that colloidal Mg2Al-UD-LDH nanosheets (obtained by ultrasonic treatment of Mg2Al-NO3-LDH suspension) achieved a higher arsenate adsorption density of 1.21 mmol/g than parent Mg2Al-NO3-LDH (1.16 mmol/g) at a solid-to-solution dosage of 0.78 g LDH/L. The adsorption mechanism of arsenate onto colloidal Mg2Al-UD-LDH nanosheets proceeded through restacking of the nanosheets, besides ion-exchange onto Mg2Al-NO3-LDH and surface adsorption onto Mg2Al-CO3-LDH. Kinetics of arsenate adsorption onto colloidal Mg2Al-UD-LDH nanosheets was rapid, reaching equilibrium within 5 min, whereas equilibrium was reached within 120 min in the presence of Mg2Al-NO3-LDH. The colloidal LDH nanosheets stacking effect was restricted at higher LDH/As ratios owing to electrostatic repulsion among the nanosheets, as determined by zeta potential measurements. Semi-pilot scale static model systems for arsenate adsorption were examined to further investigate the adsorption performance of colloidal Mg2Al-UD-LDH nanosheets in natural water systems such as river, pond, or lake. Arsenate adsorption was rapid onto colloidal Mg2Al-UD-LDH nanosheets owing to their high dispersibility; specifically, 100% adsorption efficiency was achieved within 5 min. Thus, the high adsorption capacity, dispersibility, and fast kinetics of arsenate removal onto colloidal Mg2Al-UD-LDH nanosheets promising for use as an efficient adsorbent for water remediation.
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U2 - 10.1016/j.clay.2016.06.002
DO - 10.1016/j.clay.2016.06.002
M3 - Article
AN - SCOPUS:84995739824
SN - 0169-1317
VL - 134
SP - 110
EP - 119
JO - Applied Clay Science
JF - Applied Clay Science
ER -