Immobilization of methylene blue onto bentonite and its application in the extraction of mercury (II).
Methylene blue was immobilized onto bentonite (BNT). The modified clay (MB-BNT) was used to extract Hg(2+) at pH 6.0 yielding Hg-MB-BNT. BNT, MB-BNT and Hg-MB-BNT were characterized by X-ray diffractometry, infrared spectra, and elemental and thermogravimetric analyses. MB is suggested to be intercalated into the major phase of BNT; montmorillonite mineral (MMT), lying parallel to the aluminosilicate layers, with a capacity of 36 mequiv./100g. MB-BNT shows good stability in 0.1-1M hydrochloric or nitric acids, ammonium hydroxide, and concentrated Na(+), K(+) or NH(4)(+) chlorides or iodides. It shows good selectivity towards Hg(2+) with an extraction capacity of 37 mequiv./100g in the presence of I(-) giving rise to a ratio of MB/Hg(2+)/I(-) 1:1:3 in the clay phase. Extracted Hg(2+) could be quantitatively recovered by ammonia buffer at pH 8.5. MB-BNT was successfully applied to recover Hg(2+) from spiked natural water and cinnabar mineral samples using the optimum conditions; pH 6.0, time of stirring 10 min and 10 mL of 0.05 M NH(4)Cl/NH(4)OH at pH 8.5 as eluent.
Department of Chemistry, Industrial Education College, University of Beni-Suif, Beni-Suif, Egypt.
Mohamed M
MM
Hassanien
Khaled S
KS
Abou-El-Sherbini
Nayef S
NS
Al-Muaikel
D000042:Absorption; D000465:Algorithms; D001546:Bentonite / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D008628:Mercury / Q000737:chemistry / Q000302:isolation & purification*; D017669:Mercury Compounds / Q000302:isolation & purification; D008751:Methylene Blue / Q000737:chemistry*; D052616:Solid Phase Extraction; D013054:Spectrophotometry, Atomic; D017550:Spectroscopy, Fourier Transform Infrared; D013816:Thermodynamics; D014881:Water Supply / Q000032:analysis; D014961:X-Ray Diffraction
D004396:Coloring Agents; D007202:Indicators and Reagents; D017669:Mercury Compounds; D001546:Bentonite; D008628:Mercury; D008751:Methylene Blue