Dyestuff Adsorbing Natural Composites for Wastewater Treatments
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environmentally-friendly, relatively lower cost, having lower water consumption,
and including non-hazardous metabolites. Efficiency depends on pH, temperature,
oxygen concentration, amount of microorganisms, and dyestuff because living things
are used, and their metabolism is affected by environmental conditions; thus, it needs
attention. Biological refining methods are classified into two groups as methods done
by microorganisms and enzymes [13]. If the enzymes such as ligninase (toxicity
removal), cellulase (breaking cellulose particles into glucose), peroxidase (removal
of color and peroxides), and dehalogenase (dechlorination and removal of chlorophenols) that are used by microorganisms or can degrade the impurities in the wastewater
are directly added into the refining baths, then it is enzyme-type methods. Enzymes
are specific to their substrates and only deal with them, and if the conditions as
temperature, pH, etc., are suitable, they cannot be deformed, and they can be used
more than once [16]. If the microorganisms directly used in refining and enzymes that
have in their metabolic reactions are used, then it is microorganism-type refining.
Also, refining methods with microorganisms can be divided into two subtitles as
aerobic and anaerobic refining. For example, bacterial refining can be aerobic or
anaerobic, while fungi refining is aerobic generally [17].
Aerobic biological refining methods degrade or convert impurities into less
harmful materials by using oxygen with a microorganism, especially at low-strength
wastewater which has lower COD than 1000 mg/L [17]. Aerobic refining is very
effective, especially at decolorization of dyestuffs by using microorganisms as
Pseudomonas fluorescens, Bacillus fusiformis, Staphylococcus aureus, Enterococcus
gallinarum, Brevibacillus laterosporus, etc. [18]. These methods are very good at less
odor production and efficient removing, but oxygen need, mud production, clogging,
and costs can be adverse sides of aerobic refining methods.
Anaerobic biological treatment does not need oxygen in the degradation of impurities at high strength wastewater which has higher COD than 4000 mg/L. Producing
natural gas like methane, having low mud production, and cost can be favorable sides
of anaerobic refining methods [17]. With the light of this information, if there is highstrength water, firstly, anaerobic methods are applied, and then, aerobic methods can
be added, after the organic material amount of the wastewater is suitable for aerobic
microorganisms, to yield the best sides of both methods.
All types of refining methods have some advantages and disadvantages compared
to each other, but using alternative environmentally-friendly refining processes that
decrease the process amount, chemical, and refining waste, refining cost and time
are very valuable and important for total production and environmental concern.
It provides an increase in the application of refining with better and more desired
options. If refining is easy and economical or it has any advantages over the classical
processes, then the refining gains importance, and more companies would like to
attend the environmental concern. In most cases, methods or multifunctional materials that can offer all these benefits in a single step are the needs of future applications
with growing technologies and keeping fast fashion cycles in a good manner. For
these reasons, many studies are concentrated on the development of novel refining
processes and multifunctional materials for refining.
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environmentally-friendly, relatively lower cost, having lower water consumption,
and including non-hazardous metabolites. Efficiency depends on pH, temperature,
oxygen concentration, amount of microorganisms, and dyestuff because living things
are used, and their metabolism is affected by environmental conditions; thus, it needs
attention. Biological refining methods are classified into two groups as methods done
by microorganisms and enzymes [13]. If the enzymes such as ligninase (toxicity
removal), cellulase (breaking cellulose particles into glucose), peroxidase (removal
of color and peroxides), and dehalogenase (dechlorination and removal of chlorophenols) that are used by microorganisms or can degrade the impurities in the wastewater
are directly added into the refining baths, then it is enzyme-type methods. Enzymes
are specific to their substrates and only deal with them, and if the conditions as
temperature, pH, etc., are suitable, they cannot be deformed, and they can be used
more than once [16]. If the microorganisms directly used in refining and enzymes that
have in their metabolic reactions are used, then it is microorganism-type refining.
Also, refining methods with microorganisms can be divided into two subtitles as
aerobic and anaerobic refining. For example, bacterial refining can be aerobic or
anaerobic, while fungi refining is aerobic generally [17].
Aerobic biological refining methods degrade or convert impurities into less
harmful materials by using oxygen with a microorganism, especially at low-strength
wastewater which has lower COD than 1000 mg/L [17]. Aerobic refining is very
effective, especially at decolorization of dyestuffs by using microorganisms as
Pseudomonas fluorescens, Bacillus fusiformis, Staphylococcus aureus, Enterococcus
gallinarum, Brevibacillus laterosporus, etc. [18]. These methods are very good at less
odor production and efficient removing, but oxygen need, mud production, clogging,
and costs can be adverse sides of aerobic refining methods.
Anaerobic biological treatment does not need oxygen in the degradation of impurities at high strength wastewater which has higher COD than 4000 mg/L. Producing
natural gas like methane, having low mud production, and cost can be favorable sides
of anaerobic refining methods [17]. With the light of this information, if there is highstrength water, firstly, anaerobic methods are applied, and then, aerobic methods can
be added, after the organic material amount of the wastewater is suitable for aerobic
microorganisms, to yield the best sides of both methods.
All types of refining methods have some advantages and disadvantages compared
to each other, but using alternative environmentally-friendly refining processes that
decrease the process amount, chemical, and refining waste, refining cost and time
are very valuable and important for total production and environmental concern.
It provides an increase in the application of refining with better and more desired
options. If refining is easy and economical or it has any advantages over the classical
processes, then the refining gains importance, and more companies would like to
attend the environmental concern. In most cases, methods or multifunctional materials that can offer all these benefits in a single step are the needs of future applications
with growing technologies and keeping fast fashion cycles in a good manner. For
these reasons, many studies are concentrated on the development of novel refining
processes and multifunctional materials for refining.