Modified Clay Supported Ferrioxalate Catalysts For The Degradation Of Phenol, 4-Nitrophenol And Amoxicillin Using Photo-Fenton Process
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Date
2012-01
Authors
Ayodele, Olumide Bolarinwa
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
As part of effort to ensure clean, less polluted water matrix and to ensure sustainable environment, three different types of naturally abundant clay were modified as heterogeneous catalyst support for the degradation of phenol, 4-nitrophenol (4-NP) and amoxicillin (AMX) in a batch Fenton process irradiated with ultra violet light. Acid treatment and metal pillaring techniques were used to modify kaolin and smectite (montmorrilinite and bentonite) clay samples, respectively. Two different concentrations (5 M and 10 M) of phosphoric acid were used to modify the raw kaolin (RK) clay; similarly, aluminum and copper were employed to pillar mild acid treated montmorillonite (MATM) and raw bentonite (RB) clays, respectively. The catalyst precursor was prepared by reacting iron hydroxide with oxalic acid to form ferrioxalate complexes and the catalyst synthesis was done via direct dissolution of the catalyst precursor into the suspension of the modified supports. The acid treated kaolin catalysts (ATKCs), Aluminum pillared montmorillonite catalyst (AlPMC) and the copper pillared bentonite catalyst (CuPBC) was characterized for their physical and chemical properties. The effect of acid treatment increased the surface area of RK from 19.4 to 36 m2 g-1 in 5 M acid treated kaolin catalyst (ATKC-1) and finally to 145.5 m2 g-1 in 10 M acid treated kaolin catalyst (ATKC-2). Similarly, there was dynamic degree of de-alumination in the ATKCs as the acid strength increased from 5 M to 10 M. There is also increment in the surface area from 164.9 in MATM to 211.6 m2 g-1 in AlPMC and from 18.1 in RB to 40.6 m2
g-1 in CuPBC after the pillaring process. The catalytic activity of these catalysts was tested on the degradation of phenol (100-200 ppm), 4-nitrophenol (100 -200 ppm) and amoxicillin (20-100 ppm) using hydrogen peroxide (HP) as the source of hydroxyl radical (HO•). The effects of factors affecting degradation process were studied. The best observed results showed that total degradation of 100 ppm of phenol and 4-NP were achieved in 6 min reaction time using 2.5 g each of ATKC-1 and CuPBC, respectively at 30 oC. Similarly, within 6 and 10 min reaction time,
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Keywords
Modified clay supported ferrioxalate catalysts , degradation of phenol, 4-nitrophenol and amoxicillin