6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 256
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
Abstract This chapter aims to present the effect of treating a pharmaceutical
industrial effluent by photo-Fenton catalyzed with a Fe-pillared bentonite. XRD
proved the pillaring process successful, and by N 2 physisorption, it was established
that the specific surface area of bentonite (34 m
2 /g) increased to 277 m
2 /g and pore
volume increased from 0.058 to 0.106 cm
3 /g. Active Fe species were identified by
Mössbauer spectroscopy. The effect of reaction variables such as catalyst loading,
pH, H 2 O 2 concentration, and initial concentration of total organic carbon (TOC) is
also presented. It was concluded that to reach near 100% mineralization, an acidic
pH (2.7) should be observed. A high mineralization under these conditions, however, does not directly correlate with a low toxicity. Actually, the oxidative stress
biomarkers only decreased when pH was not modified (pH ¼ 8) albeit the attained
mineralization was only 51%. It is worth noticing that the use of pillared clays allows
carrying out photo-Fenton treatment under pH conditions other than acidic. The
synthesized catalyst exhibited magnetism and this can be used for an easier recovery.
Keywords AOPs, Emerging contaminants, Mineralization, Photocatalysis,
Toxicity, Wastewater
1 Introduction
The pharmaceutical production is one of the biggest problems related to water
pollution. In Mexico, it has been shown that pharmaceutical industry effluents are
a mixture of a variety of compounds frequently toxic [1], which include excipients,
pharmaceutical drugs, and washing products. In this context, the effluents of production processes of emerging contaminants, such as nonsteroidal anti-inflammatory
drugs (NSAIDs), are receiving special attention. Among NSAIDs, paracetamol or
acetaminophen stands out because worldwide it is highly consumed and therefore
highly produced. The importance of effective treatment of paracetamol containing
effluents is related to toxicological effects in aquatic environment [2], since the
degradation products of paracetamol are potentially toxic, causing on indicator
species oxidative stress and cellular damage or death and inhibition of reproduction
[3]. This has motivated the study and development of processes that contribute to the
treatment of theses pollutants. Particularly attractive options are the advanced
oxidation processes (AOPs). Among these, there are the well-known Fenton and
photo-Fenton processes. The Fenton process involves the reaction of Fe(II) with
H 2 O 2 to produce hydroxyl radicals (HO
. ) via reaction 1. Under suitable conditions,
the process is considered catalytic due to the reduction of Fe(III) by reactions 2 and
242
R. Natividad et al.
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257
Abstract This chapter aims to present the effect of treating a pharmaceutical
industrial effluent by photo-Fenton catalyzed with a Fe-pillared bentonite. XRD
proved the pillaring process successful, and by N 2 physisorption, it was established
that the specific surface area of bentonite (34 m
2 /g) increased to 277 m
2 /g and pore
volume increased from 0.058 to 0.106 cm
3 /g. Active Fe species were identified by
Mössbauer spectroscopy. The effect of reaction variables such as catalyst loading,
pH, H 2 O 2 concentration, and initial concentration of total organic carbon (TOC) is
also presented. It was concluded that to reach near 100% mineralization, an acidic
pH (2.7) should be observed. A high mineralization under these conditions, however, does not directly correlate with a low toxicity. Actually, the oxidative stress
biomarkers only decreased when pH was not modified (pH ¼ 8) albeit the attained
mineralization was only 51%. It is worth noticing that the use of pillared clays allows
carrying out photo-Fenton treatment under pH conditions other than acidic. The
synthesized catalyst exhibited magnetism and this can be used for an easier recovery.
Keywords AOPs, Emerging contaminants, Mineralization, Photocatalysis,
Toxicity, Wastewater
1 Introduction
The pharmaceutical production is one of the biggest problems related to water
pollution. In Mexico, it has been shown that pharmaceutical industry effluents are
a mixture of a variety of compounds frequently toxic [1], which include excipients,
pharmaceutical drugs, and washing products. In this context, the effluents of production processes of emerging contaminants, such as nonsteroidal anti-inflammatory
drugs (NSAIDs), are receiving special attention. Among NSAIDs, paracetamol or
acetaminophen stands out because worldwide it is highly consumed and therefore
highly produced. The importance of effective treatment of paracetamol containing
effluents is related to toxicological effects in aquatic environment [2], since the
degradation products of paracetamol are potentially toxic, causing on indicator
species oxidative stress and cellular damage or death and inhibition of reproduction
[3]. This has motivated the study and development of processes that contribute to the
treatment of theses pollutants. Particularly attractive options are the advanced
oxidation processes (AOPs). Among these, there are the well-known Fenton and
photo-Fenton processes. The Fenton process involves the reaction of Fe(II) with
H 2 O 2 to produce hydroxyl radicals (HO
. ) via reaction 1. Under suitable conditions,
the process is considered catalytic due to the reduction of Fe(III) by reactions 2 and
242
R. Natividad et al.