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Sorptive Removal of Trinitroglycerin (TNG) from Water Using Nanostructured Silica‐based Materials
Author(s) -
Saad Rabih,
Thibutot Sonia,
Ampleman Guy,
Hawari Jalal
Publication year - 2010
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2009.0275
Subject(s) - sorption , desorption , sorbent , endothermic process , chemical engineering , enthalpy , chemistry , langmuir , langmuir adsorption model , adsorption , materials science , environmental chemistry , organic chemistry , physics , quantum mechanics , engineering
Trinitroglycerin (TNG), a nitrate ester, is widely used in the pharmaceutical industry for the treatment of angina pectoris (chest pain) and by the military for the manufacturing of dynamite and propellants. Currently, TNG is considered as a key environmental contaminant due to the discharge of wastewater tainted with the chemical from various military and pharmaceutical industries. The present study describes the use of a nanostructured silica material (Mobil Composite Material no. 48 [MCM‐48]) prepared by mixing tetraethylorthosilicate (TEOS) and cetyltrimethylammonium bromide (CTAB) to remove TNG from water. The sorption of TNG onto MCM‐48 rapidly reached equilibrium within 1 h. Sorption kinetics were best described using a pseudo‐second order model, whereas sorption isotherms were best interpreted using the Langmuir model. The latter gave a maximum sorption capacity of 55.2 mg g −1 at 40°C. The enthalpy and entropy of TNG sorption onto MCM‐48 were 1.89 kJ mol −1 and 79.0 J mol −1 K −1 , indicating the endothermic nature of the TNG sorption onto MCM‐48. When MCM‐48 was heated at 540°C for 5 h, the resulting calcined material (absence of the surfactant) did not sorb TNG, suggesting that the surfactant component of the nanomaterial was responsible for TNG sorption. Finally, we found that MCM‐48 lost approximately 30% of its original sorption capacity after five sorption–desorption cycles. In conclusion, the nanostructured silica based sorbent, with high sorption capacity and remarkable reusability, should constitute the basis for the development of an effective technology for the removal of TNG from contaminated water.