NSAIDs wastewater removal is becoming a major concern in environmental protection. New technologies capable of efficiently removing them have been developed in
the last few decades, and, within them, nanotechnology has risen as a promising tool
to aid these technologies to accomplish their goal. In this chapter, the most common
approaches to treat NSAIDs-containing wastewater are addressed, including adsorption, photocatalysis, and electrocatalysis; besides, recent advances on nanotechnological applications to improve their performance are covered.
Keywords Adsorbents, Electrocatalyst, Nanomaterials, NSAIDs, Photocatalyst,
Removal
1 Introduction
NSAIDs are active pharmaceutical ingredients (APIs), which are among the most
common molecules used in the treatment of rheumatic or degenerative joint diseases
and in pain relief and muscle inflammation. This category includes ibuprofen,
aspirin, indomethacin, ketorolac, naproxen, acetaminophen, sulindac, nimesulide,
and diclofenac, among others (Fig. 1) [1–3]. However, several biologically active
metabolization products are excreted into domestic effluents, easily reaching water
effluents; furthermore, as they are over-the-counter drugs, these emerging pollutants
are becoming a serious concern to public health due to their growing environmental
presence. Diclofenac, ibuprofen, and naproxen are in the top ten of persistent
pollutants found in wastewater; besides, they exhibit specific properties that draw
concerns on their potential environmental and health impacts: they can passively
diffuse across biological membranes, have low pK a values, and are highly persistent
in aquatic environments [4, 5]. Several methods have been assayed to remove
NSAIDS from water effluents such as ozonation [6], chloride oxidation [7], coagulation [8], reverse osmosis [9], reusable ionic-liquid extraction [10], and activated
sludges, [11] among others, but most of them are highly energy-intensive and
present a low efficiency compared to their cost. Therefore, novel, high-performance
alternatives are required.
Due to their inherent nature, pharmaceuticals are resistant to physical and chemical changes and persist after conventional wastewater treatment. In several conditions, most of them are not efficiently adsorbed on conventional adsorbents, and,
what is even worse, some steps in the traditional treatment such as chlorination can
generate more toxic degradation products. Therefore, there is a need to develop
novel, low-cost adsorbents with high adsorption capacity and reusability in order to
concentrate these contaminants and separate them from their aqueous matrices for
further proper disposal. On the other hand, there is a need to finally destroy these
compounds. As an alternative, several catalytic methods have been developed in the
last decades; mostly oxidative, these methods intend to decompose pollutants into
smaller, safer molecules, ideally into CO 2 and H 2 O.
278
M. Cerro-Lopez et al.
the last few decades, and, within them, nanotechnology has risen as a promising tool
to aid these technologies to accomplish their goal. In this chapter, the most common
approaches to treat NSAIDs-containing wastewater are addressed, including adsorption, photocatalysis, and electrocatalysis; besides, recent advances on nanotechnological applications to improve their performance are covered.
Keywords Adsorbents, Electrocatalyst, Nanomaterials, NSAIDs, Photocatalyst,
Removal
1 Introduction
NSAIDs are active pharmaceutical ingredients (APIs), which are among the most
common molecules used in the treatment of rheumatic or degenerative joint diseases
and in pain relief and muscle inflammation. This category includes ibuprofen,
aspirin, indomethacin, ketorolac, naproxen, acetaminophen, sulindac, nimesulide,
and diclofenac, among others (Fig. 1) [1–3]. However, several biologically active
metabolization products are excreted into domestic effluents, easily reaching water
effluents; furthermore, as they are over-the-counter drugs, these emerging pollutants
are becoming a serious concern to public health due to their growing environmental
presence. Diclofenac, ibuprofen, and naproxen are in the top ten of persistent
pollutants found in wastewater; besides, they exhibit specific properties that draw
concerns on their potential environmental and health impacts: they can passively
diffuse across biological membranes, have low pK a values, and are highly persistent
in aquatic environments [4, 5]. Several methods have been assayed to remove
NSAIDS from water effluents such as ozonation [6], chloride oxidation [7], coagulation [8], reverse osmosis [9], reusable ionic-liquid extraction [10], and activated
sludges, [11] among others, but most of them are highly energy-intensive and
present a low efficiency compared to their cost. Therefore, novel, high-performance
alternatives are required.
Due to their inherent nature, pharmaceuticals are resistant to physical and chemical changes and persist after conventional wastewater treatment. In several conditions, most of them are not efficiently adsorbed on conventional adsorbents, and,
what is even worse, some steps in the traditional treatment such as chlorination can
generate more toxic degradation products. Therefore, there is a need to develop
novel, low-cost adsorbents with high adsorption capacity and reusability in order to
concentrate these contaminants and separate them from their aqueous matrices for
further proper disposal. On the other hand, there is a need to finally destroy these
compounds. As an alternative, several catalytic methods have been developed in the
last decades; mostly oxidative, these methods intend to decompose pollutants into
smaller, safer molecules, ideally into CO 2 and H 2 O.
278
M. Cerro-Lopez et al.