title: Effective uptake of decontaminating agent (citric acid) from aqueous solution by mesoporous and microporous materials: an adsorption process.
abstract: The presence of citric acid in decontamination waste can cause complexation of the radioactive cations resulting in interferences in their removal by various treatment processes such as chemical precipitation, ion-exchange, etc., which are employed for the removal of radioactivity and may cause potential danger to the environment. Mesoporous Al-MCM-41 (Si/Al=30, 51, 72 and 97) and Si-MCM-41 molecular sieves were synthesized hydrothermally and characterized by XRD, BET (surface area) and FT-IR to evaluate the removal of citric acid through an adsorption process. Adsorption of citric acid over Al-MCM-41 shows the applicability of Freundlich and Langmuir isotherm and follows first order kinetics. The effects of contact time, concentration of citric acid, adsorbents (various Si/Al ratios of Al-MCM-41, Si-MCM-41, Hbeta zeolite and commercial carbon) and pH have been investigated. It has been found that the amount of citric acid adsorbed per unit gram of catalyst followed the order Al-MCM-41 (Si/Al=30)>Al-MCM-41 (Si/Al=51)>activated charcoal>Al-MCM-41 (Si/Al=72)>Al-MCM-41 (Si/Al=97)>Si-MCM-41>Hbeta zeolite.
authors.affiliation: Department of Chemistry, Anna University, Chennai 600 025, India.
authors.forename: Narasimhan
authors.initials: N
authors.lastname: Gokulakrishnan
authors.forename: Arumugam
authors.initials: A
authors.lastname: Pandurangan
authors.forename: Pradeep Kumar
authors.initials: PK
authors.lastname: Sinha
mesh_terms: D000327:Adsorption; D000535:Aluminum / Q000737:chemistry*; D002384:Catalysis; D002606:Charcoal / Q000737:chemistry; D002614:Chelating Agents / Q000737:chemistry / Q000302:isolation & purification*; D019343:Citric Acid / Q000737:chemistry / Q000302:isolation & purification*; D016062:Porosity; D012825:Silicon / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D017641:Zeolites; D002606:Charcoal; D019343:Citric Acid; D000535:Aluminum; D012825:Silicon