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A. Mazumder et al.
1 Introduction
For the last three decades, membrane separation technology has gained popularity
as an advanced separation method and is presently considered to be one of the expedient separation processes in the field of wastewater treatment. A wide range of
industries including chemical, pharmaceutical, biotechnological, automobile, dairy
industries, etc. have adopted this technology as their wastewater treatment method.
Major benefits of membrane technology over other conventional separation technologies include selective separation, recovery of valuable by-products, nonrequirement
of additional chemical dosage, reduction in the number of unit operations, easy
operability, and low space requirement (Putatunda et al. 2019). However, the major
hurdle associated with any membrane process is membrane fouling. In the case of
fouling, permeate flux declines due to gradual pore blockage and cake layer formation during operation under constant transmembrane pressure (TMP). Reversible
membrane fouling and irreversible membrane fouling are the two major categories of
fouling. Reversible membrane fouling occurs due to the evolution of the cake layer on
the membrane surface and can be removed by backwashing. In the case of irreversible
one, membrane pore blockage occurs and is challenging to remove (Guo et al. 2012).
Frequent membrane replacement being an expensive process, appropriate membrane
cleaning strategy is utmost required. To eradicate irreversible membrane fouling,
different chemical cleaning agents are utilized, which include acids, alkalis, surfactants, oxidants, enzymes, and chelating components. Moreover, the development of
biofilms on the membrane surface owing to the presence of a high load of organic
components is an unwanted common phenomenon and is commonly controlled to
some extent by the addition of disinfectants (Shi et al. 2014). But complete removal
and mitigation of biofouling need special cleaning solutions having antimicrobial
activities. Thus, the optimization of membrane cleaning through the use of low-cost
and effective chemical cleaning agents is a strenuous assignment. In this context,
the present study concentrates on the development of a new cost-effective cleaning
agent (metallosurfactant) having the ability to remove sticky oil foulants from the
membrane during the membrane separation of oily wastewater.
2 Overview on Metallosurfactant
Metallosurfactant has grasped the enormous attention of worldwide research communities by their exclusive surface activity. It represents an advanced class of surfactant
where a central metal is induced in the polar head group of the conventional surfactant molecule as an intrinsic structural part. The embodiment of d-or-f block metal
ions into the polar head of the surfactant system by coordination bond forms metallosurfactant, which enriches different properties of ordinary surfactants by increasing
the surface-active efficiency (Kumaraguru and Santhakumar 2009). The coordination bond is formed by the transition metals with ligands by accepting electron pairs.
A. Mazumder et al.
1 Introduction
For the last three decades, membrane separation technology has gained popularity
as an advanced separation method and is presently considered to be one of the expedient separation processes in the field of wastewater treatment. A wide range of
industries including chemical, pharmaceutical, biotechnological, automobile, dairy
industries, etc. have adopted this technology as their wastewater treatment method.
Major benefits of membrane technology over other conventional separation technologies include selective separation, recovery of valuable by-products, nonrequirement
of additional chemical dosage, reduction in the number of unit operations, easy
operability, and low space requirement (Putatunda et al. 2019). However, the major
hurdle associated with any membrane process is membrane fouling. In the case of
fouling, permeate flux declines due to gradual pore blockage and cake layer formation during operation under constant transmembrane pressure (TMP). Reversible
membrane fouling and irreversible membrane fouling are the two major categories of
fouling. Reversible membrane fouling occurs due to the evolution of the cake layer on
the membrane surface and can be removed by backwashing. In the case of irreversible
one, membrane pore blockage occurs and is challenging to remove (Guo et al. 2012).
Frequent membrane replacement being an expensive process, appropriate membrane
cleaning strategy is utmost required. To eradicate irreversible membrane fouling,
different chemical cleaning agents are utilized, which include acids, alkalis, surfactants, oxidants, enzymes, and chelating components. Moreover, the development of
biofilms on the membrane surface owing to the presence of a high load of organic
components is an unwanted common phenomenon and is commonly controlled to
some extent by the addition of disinfectants (Shi et al. 2014). But complete removal
and mitigation of biofouling need special cleaning solutions having antimicrobial
activities. Thus, the optimization of membrane cleaning through the use of low-cost
and effective chemical cleaning agents is a strenuous assignment. In this context,
the present study concentrates on the development of a new cost-effective cleaning
agent (metallosurfactant) having the ability to remove sticky oil foulants from the
membrane during the membrane separation of oily wastewater.
2 Overview on Metallosurfactant
Metallosurfactant has grasped the enormous attention of worldwide research communities by their exclusive surface activity. It represents an advanced class of surfactant
where a central metal is induced in the polar head group of the conventional surfactant molecule as an intrinsic structural part. The embodiment of d-or-f block metal
ions into the polar head of the surfactant system by coordination bond forms metallosurfactant, which enriches different properties of ordinary surfactants by increasing
the surface-active efficiency (Kumaraguru and Santhakumar 2009). The coordination bond is formed by the transition metals with ligands by accepting electron pairs.