Khoáng hóa metyl da cam bằng hiệu ứng fenton điện hóa sử dụng catốt composit polypyrrol/oxit

TAP CHi KHOA HOC VA CONG NGHE Tap 48, so 1, 2010 Tr. 105-112

KHOANG HOA METYL DA CAM BANG HIEU l/NG FENTON OIEN

HOA Sir DUNG CATOT COMPOSIT POLYPYRROL/OXIT

NGUYE N TH! LE HltN, HOAN G THj MY HANH

1. MOf DAU

Cac chat mau hg azo hau het deu cd cau tao mach cacbon phiic tap, cdng kenh, khd hi phan

huy bang cac phuang phap tmyen thdng: sinh hgc, vat li, hoa hgc... Fenton dien hoa la mdt trong

cac phuong phap oxy hda tien tien cd kha nang khoang hda cac hgp chat mau hg azo vdi hieu

qua cao va hiia hen nhieu trien vgng trong viec xu li nudc thai cdng nghiep det nhudm chiia chat

mang mau [1 - 3]. Fenton dien hda la qua trinh khu oxy hda tan tien dien cue catdt tao ra H2O2,

H2O2 sinh ra cd kha nang dxy hda kim loai chuyen tiep nhu Fe^"^, Co^"^, Cu"^... cd mat trong dung

dich tao gdc OH*. Cac gdc HO* tao thanh cd tinh oxi hoa rat manh, cd the oxi hoa hoan toan hau

het cac hgp chat hiiu co doe hai tao thanh CO2 va H2O.

Hieu suat cua phan iing Fenton dien hda phu thudc vao rat nhieu yeu td, trong dd vat lieu

lam dien cue catdt la mdt tiong cac yeu td quan trgng nhat, quyet dinh tdc do tao H2O2, la tac

nhan oxy hda trong he Fenton. Cac nghien ciiu trudc day da chi ra rang dien cue composit tren

CO sd polypyrol va oxit phiic hgp cau tnic spinel Cui_5Mni_504 (Ppy/Cui^sMn 1^504) cho kha nang

xiic tac dien hda phan iing khii oxy tao H2O2 vdi hieu suat cao trong mdi trudng axit pH = 3 [4],

cho phep ling dung nhu dien cue catdt khoang hda phenol [5], methyl dd [6]... bang phuong

phap Fenton dien hda. Trong khudn khd bai bao nay, chiing tdi khao sat qua trinh khoang hda

metyl da cam (MO) - mdt hgp chat diazo dien hinh khd phan hiiy va ddc hai bang hieu iing

Fenton dien hda tren dien cue catdt composit Ppy/Cui,5Mni,504.

2. DIEU KIEN THU C NGHIEM

Cac qua trinh dien hda dugc thuc hien trong binh dien hda he ba dien cue vdi dien cue lam

viec la graphit phu mang Ppy chiia hoac khdng chiia oxit Cui_5Mni_504, dien tich 5 cm^, dien cue

ddi la ludi platin va dien cue so sanh la calomen bao hda KCI, tren thiet bi Autolab (Ha Lan)

dugc dat tai Vien Ky thuat nhiet ddi.

Dien cue polyme dan dugc tdng hgp tren nen cacbon bang phuong phap dien hda trong

dung dich KCI 0,5 M, Ppy 0,1 M cd hoac khdng' chiia oxit Cui,5Mni,504, tai mat do ddng

2 mA/cm^ vdi dien tich tdng hgp la 2 C/cm^ [5].

Qua trinh xtr li metyl da cam bang hieu ung Fenton dien hda dugc thuc hien trong dung

dich Na2S04 0,05 M, Fe^^ 1 mM pH=3 chiia metyl da cam ndng do 1,53 mM, tai mat do ddng

dien 1 mA/cm^. Dung dich dugc sue oxy vdi tdc do 0,5 l/phiit.

Su suy giam cac hgp chat hiiu co trong qua trinh xii li dugc xae dinh nhd phd hap thu UV￾Vis va nhu ciu oxy hda hgc (COD).

Hieu suat phan buy metyl da cam (r\) dugc tinh thdng qua do hap phu (A) nhu sau:

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