Tuning water chemistry for the recovery of greener products: pragmatic and sustainable approaches
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Date
2023-02-17
Journal Title
Journal ISSN
Volume Title
Publisher
Royal Sociaty of Chemistry
Abstract
The early techniques for recovery of bioactive metabolites
involve conventional cold or hot solvent extraction.1 The choice
is a function of the nature of the bioactive compound of
interest.2 The adverse effect of organic solvents (Table 1) which
are mostly preferred extraction techniques has warranted the
search for greener alternatives. One of the ways green extrac tions is described involves the isolation of medicinally active
portions from a bio-material,3 with the simultaneous use of eco friendly solvents and optimal use of energy.4–9 Prospecting for
green solvents has brought water to the fore of extraction
technology.10 Water is affirmatively described as the “greenest
solvent” imaginable, with its availability at the required purity,
it is cost-effective, readily recycled, non-toxic, non-ammable,
and eco-friendly.10–13 Based on the green chemistry precept,
water is considered a green chemical per excellence.14–16 Water
is useful in the recovery of various phytochemicals including
alcohols, sugars, proteins, and organic acids with natural water soluble properties.12,16–21 However, water as a solvent has some
physical and chemical property disadvantages when compared
to organic solvent.21–23 The polar nature of water in its natural
form reduces its efficacy and acceptability when compared with
organic solvents for some kinds of extractions. Organic solvents
are extensively desirable since they exhibit better recovery than
water at ambient conditions.3 Further setbacks experienced
when using conventional hydro-extraction include time and
energy consumption, thermal decomposition of thermo sensitive metabolites and low recovery of hydro-solvent in its
natural form.
There exists the need to investigate water properties that can
be improved to complement its natural advantage and eradicate
its attendant limitations as a solvent for extraction.5,8,10,28,29 have
indicated that improving traditional extraction must entail
decreased energy input, sustainability and a non-toxic nal
product. Improving water to own variable chemistry will aid the
extraction of a broad range of polar and non-polar biomolecules
from sustainable natural products with non-toxic quality and
eco-friendliness.10,21,29 This approach will prevent the use of
organic solvents, fossil energy, chemical waste and risks of
extraction. It is known that water existing in its tunable form
satises the conditions of green solvents.11–13 Recently, the
Sustainable Development Goals
SDG 3: Good Health and Well-being
SDG 6: Clean Water and Sanitation
SDG 7: Affordable and Clean Energy
SDG 9: Industry, Innovation, and Infrastructure
Keywords
water chemistry, organic solvents, water properties