Page 30 - HPIC India

Cover Story

of the light spectrum and transmits the wash liquor, with high electro- ing from using bleach solutions gene-
it to the oxygen molecules available lyte concentration in the formulation. rally do not appear to be irritating, but
in water. The activated oxygen [O *] As bleaching depends on the natural more harmful fumes can arise when
2
is then able to oxidise stains and environmental conditions, the light hypochlorite bleaches are mixed with
micro-organisms to provide a clean, intensity, air humidity, drying con- certain acidic products. Strict adherence
hygienic laundering even at low tem- ditions and temperature all have an to the manufacturers’ recommendations
perature. The PBA exhausts on to influence, in effective bleaching. It on usage is necessary.
the cellulosic fibres from the alkaline is especially suitable for use in the
detergent liquors used for washing. Indian subcontinent with high sunlight Bleach solutions are very toxic to
energy, where wash habits involve aquatic life at concentrations as low as
Tinolux BBS is an anionic dark soaking, for at least 5 to 10 minutes 0.01mg/L. However, household bleach
blue aqueous liquid, having a pH and the washed fabric is line-dried in solutions rapidly break down when it
of around 5.8 that is incorporated the open, exposed in sunlight. comes across mixed sewage containing
into detergent powders, bars, li- inorganic and organic compounds, re-
quid detergents and rinsing agents PBAs are stable to storage under ducing to form inorganic chloride ions.
at 0.01 to 0.09% (w/w) of the formu- normal storage conditions; however,
lation. When added to the slurry in care must be taken to prevent expo- Tests conducted on sodium perbo-
the crutcher it gives a light blue or sure of the product as such or its rate show very slight acute toxicity.
pastel shade detergent. Quantum is solution to light. Prolonged exposure Prolonged contact with concentrated
a dark green aqueous liquid and is to temperatures above 70°C leads to solutions can cause skin and mucous
used in a similar fashion. Dry mixing partial decomposition. It also has lim- membrane irritation, which is more due
of a PBA in form of granules can pro- ited stability to chlorine at higher tem- to the alkalinity of the solution rather
duce a detergent powder with blue or peratures and at pH levels above 12. In than the ingredient by itself. Sodium
green speckles. PBAs are converted a detergent formulation PBAs can be perborate undergoes rapid hydrolysis
into solid granular form by physical used either as a single active PBA or in and the physiological effect is similar
mixing with solid substrates like combination with sodium perborate, or to borate or boric acid, which pass read-
anhydrous sodium carbonate, anhy- sodium perborate plus activator. ily through the mucous membrane or
drous sodium sulphate, sodium tri- through broken skin surface. Intact skin
polyphosphate, sodium triphosphate, The slight bluing effect imparted does prevent excessive absorption. A
starch, citric acid, other dicarboxylic on the washed fabric, by use of Tinolux dose of 18 to 20g in adults is considered
acids, bentonite clay, etc. BBS enhances the efficiency of a distyryl to be lethal. In the wastewater systems,
biphenyl type fluorescent whitening sodium perborate rapidly decomposes to
Laundrosil RT is a blue bentonite agent (FWA) that exhibit excellent wet free hydrogen peroxide, and at concen-
agglomerate containing Tinolux BBS and dry light stability, (e.g., Tinopal trations available in detergent formula-
as an active PBA. CBS-X). Conventional stilbene FWA’s tions show no toxicity to bacteria.
have a very limited light stability in the
When PBA is to be incorporated wash liquor and poor light fastness on The ecological factor that must
into a detergent powder as granules, the fabric, photodegrading to coloured be considered is the increased boron
one should take care that the granu- end products when exposed to sunlight concentration levels. Boron at levels
lar agglomerate disintegrates and and is to be avoided in a PBA based of 1-2 mg/L, posses phytotoxicity to
disperses itself in the wash liquor detergent formulation. plants like tomatoes, fruit trees and
to prevent the risk of localised ac- vineyards. It is therefore not recom-
tion of the PBA on the fabric. PBAs Toxicology & environmental aspects mended to recycle boron-containing
bleach soils that can be oxidised by Present available evidence sug- wastewater for agricultural purposes.
activated oxygen like tea, coffee, gests that solutions containing up to
red wine, fruit juices, spices, egg- 5% of sodium hypochlorite cause irri- TAED is a mild irritant to skin
yolk, grass, sauces, vegetable stains, tation on prolonged contact with skin and eyes. It is non-sensitising, non-
etc. The bleaching efficacy of a PBA or if they get into the eye. At concen- mutagenic and biodegradable with
strongly depends on the detergent trations of 10% and above burning of low toxicity to fish.
formulation and the concentration of eyes and skin can occur. Although
the wash liquor. Maximum substan- hypochlorite does not appear to cause Extensive testing on animals and
tivity of the bleach active component skin sensitisation, prolonged exposure the present state of knowledge has
is achieved at a pH value of 9-11 in can cause skin allergy. Fumes emanat- confirmed that PBAs are safe and can
30 Home, Personal & Institutional Care India November 2020