INDIA WATER WEEK 2013SESSION

“WASTEWATER MANAGEMENT - RECYCLING AND REUSE”

PAPER TITLE

“CHLOROPHENOLICS OXIDATION FROM PULP BLEACHING EFFLUENTS

USING PHOTOCATALYSIS”

AMITY UNIVERSITY HARYANA , GURGAON (MANESAR)

CONTRIBUTORSPARVEEN KUMAR, SATISH KUMAR, NISHI KANT BHARDWAJ

e-mail: parveenenv@gmail.com

Pulp bleaching Use of chlorine – AOX (chloro-organics) Pollution prevention measures: Pulp bleaching technology improvement Biological treatment Advanced oxidation treatment (Photocatalysis: UV/TiO2, UV/TiO2/H2O2 , UV/O3/TiO2 etc.)

INTRODUCTION

Characterization of chlorophenolics generated during

bleaching of mixed hardwood kraft pulp using DEPD

sequence.

Photocatalytic oxidation of chlorophenolics by

effluent treatment with UV/TiO2 and UV/TiO2/H2O2

processes.

OBJECTIVES

EXPERIMENTAL

Mixed hardwood kraft pulp (K.N. 15)

ClO2 produced in-situ from NaClO2

pH adjusted: 1M H2SO4 / 1M NaOH solution

NaOH solution: alkaline extraction of pulp

Target brightness: 87% ISO with DEPD sequence

Chlorine demand (%) = K.N. × K.F. Bleaching performed: 200 g O.D. pulp

TiO2 (Fisher Scientific): Anatase (99.97 wt.%), BET surface

area - 26.11 m2/g, Particle size - 50-150 nm)

PHOTOCATALYTIC REACTOR

Parameters D1 Stage EP Stage

COD (mg/L) 813 673

BOD (mg/L) 212 168

BOD/COD 0.26 0.25

Color (mg/L Pt-Co) 980 1113

pH 3.3 10.5

AOX (mg/L) 18 15.3

RESULTS AND DISCUSSION

ANALYTICAL CHARACTERISTICS OF THE EFFLUENTS

ChlorophenolicsInitial con.

(µg/L)

Removal (%)

UV/TiO2 UV/TiO2/H2O2

D1 EP D1 EP D1 EP

3-chlorophenol 0.11 1.35 92 56 97 64

4-chlorophenol 0.04 0.02 81 87 96 ND

2,6-dichlorophenol 0.04 ND 86 ----- ND -----

2,5-dichlorophenol 0.13 0.61 93 89 89 92

2,4-dichlorophenol 0.01 0.02 84 92 91 ND

3,4-dichlorophenol 0.04 0.04 77 75 79 81

4-chloroguaiacol 1.56 4.39 58 52 65 59

2,4,5-trichlorophenol 0.09 0.07 86 87 93 97

4,5-dichloroguaiacol 4.12 6.00 47 46 54 55

CHLOROPHENOLICS OXIDATION FROM D1 AND EP STAGE EFFLUENTS USING UV/TiO2 AND UV/TiO2/H2O2 PROCESSES

ChlorophenolicsInitial con.

(µg/L)

Removal (%)

UV/TiO2 UV/TiO2/H2O2

D1 EP D1 EP D1 EP

2,3,4-trichlorophenol 0.06 0.06 79 84 93 954,6-dichloroguaiacol 0.03 0.06 ND 90 ND 953,6-dichlorocatechol 2.14 ND 59 ----- 66 -----3,5-dichlorocatechol 0.62 ND 83 ----- 91 -----3,4,5-trichloroguaiacol 0.01 ND 82 ----- ND -----4,5,6-trichloroguaiacol ND 0.05 ----- ND ----- ND5,6-dichlorovanillin ND 0.06 ----- 74 ----- 78Tetrachlorocatechol 0.25 0.18 83 90 88 ND2,6-dichlorosyringaldehyde ND 0.22 ----- 83 ----- 86

Total 9.3 13.1 57 53 64 61

CONTINUED……..

CHLOROPHENOLICS REMOVAL BY CHEMICAL FAMILY

Removal (%) of chlorophenolics by chemical family for D1 stage effluent

Removal (%) of chlorophenolics by chemical family for EP stage effluent

CHLOROPHENOLICS REMOVAL BY NUMBER OF ATTACHED CHLORINE ATOMS

Removal (%) of chlorophenolics by number of attached chlorine atoms for D1 stage effluent

Removal (%) of chlorophenolics by number of attached chlorine atoms for EP stage effluent

CONCLUSIONS The experimental findings show that TiO2 photocatalysis is

an attractive technique for the oxidation of chlorophenolics from pulp bleaching effluents.

Higher pollutants removal efficiency was achieved with UV/TiO2/H2O2 process as compared with UV/TiO2.

The biodegradability of the effluents improved after

photocatalytic oxidation with both the processes. This indicates easy removal of the degradation products during biological treatment.

The photocatalysis, using solar light as an economical light source, may be a potential technology in future for remediation of biorecalcitrant pollutants.

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