Abstract: All around the world pulp and paper industries are the
biggest plant production with the environmental pollution as the
biggest challenge facing the pulp manufacturing operations. The
concern among these industries is to produce a high volume of papers
with the high quality standard and of low cost without affecting the
environment. This result obtained from this bleaching study show
that the activation of peroxide was an effective method of reducing
the total applied charge of chlorine dioxide which is harmful to our
environment and also show that softwood and hardwood Kraft pulps
responded linearly to the peroxide treatments. During the bleaching
process the production plant produce chlorines. Under the trial stages
chloride dioxide has been reduced by 3 kg/ton to reduce the
brightness from 65% ISO to 60% ISO of pulp and the dosing point
returned to the E stage charges by pre-treating Kraft pulps with
hydrogen peroxide. The pulp and paper industry has developed
elemental chlorine free (ECF) and totally chlorine free (TCF)
bleaching, in their quest for being environmental friendly, they have
been looking at ways to turn their ECF process into a TCF process
while still being competitive. This prompted the research to
investigate the capability of the hydrogen peroxide as catalyst to
reduce chloride dioxide.
Abstract: Chlorine is one of the most abundant elements in
nature, which undergoes a complex biogeochemical cycle. Chlorine
bound in some substances is partly responsible for atmospheric ozone
depletion and contamination of some ecosystems. As due to
international regulations anthropogenic burden of volatile
organochlorines (VOCls) in atmosphere decreases, natural sources
(plants, soil, abiotic formation) are expected to dominate VOCl
production in the near future. Examples of plant VOCl production are
methyl chloride, and bromide emission from (sub)tropical ferns,
chloroform, 1,1,1-trichloroethane and tetrachloromethane emission
from temperate forest fern and moss. Temperate forests are found to
emit in addition to the previous compounds tetrachloroethene, and
brominated volatile compounds. VOCls can be taken up and further
metabolized in plants. The aim of this work is to identify and
quantitatively analyze the formed VOCls in temperate forest
ecosystems by a cryofocusing/GC-ECD detection method, hence
filling a gap of knowledge in the biogeochemical cycle of chlorine.
Abstract: There are few studies on eggshell of leatherback turtle
which is endangered species in Thailand. This study was focusing on
the ultrastructure and elemental composition of leatherback turtle
eggshells collected from Andaman Sea Shore, Thailand during the
nesting season using scanning electron microscope (SEM). Three
eggshell layers of leatherback turtle; the outer cuticle layer or
calcareous layer, the middle layer or middle multistrata layer and the
inner fibrous layer were recognized. The outer calcareous layer was
thick and porosity which consisted of loose nodular units of various
crystal shapes and sizes. The loose attachment between these units
resulted in numerous spaces and openings. The middle layer was
compact thick with several multistrata and contained numerous
openings connecting to both outer cuticle layer and inner fibrous
layer. The inner fibrous layer was compact and thin, and composed of
numerous reticular fibers. Energy dispersive X-ray microanalysis
detector revealed energy spectrum of X-rays character emitted from
all elements on each layer. The percentages of all elements were
found in the following order: carbon (C) > oxygen (O) > calcium
(Ca) > sulfur (S) > potassium (K) > aluminum (Al) > iodine (I) >
silicon (Si) > chlorine (Cl) > sodium (Na) > fluorine (F) >
phosphorus (P) > magnesium (Mg). Each layer consisted of high
percentage of CaCO3 (approximately 98%) implying that it was
essential for turtle embryonic development. A significant difference
was found in the percentages of Ca and Mo in the 3layers. Moreover,
transition metal, metal and toxic non-metal contaminations were
found in leatherback turtle eggshell samples. These were palladium
(Pd), molybdenum (Mo), copper (Cu), aluminum (Al), lead (Pb), and
bromine (Br). The contamination elements were seen in the outer
layers except for Mo. All elements were readily observed and
mapped using Smiling program. X-ray images which mapped the
location of all elements were showed. Calcium containing in the
eggshell appeared in high contents and was widely distributing in
clusters of the outer cuticle layer to form CaCO3 structure. Moreover,
the accumulation of Na and Cl was observed to form NaCl which was
widely distributing in 3 eggshell layers. The results from this study
would be valuable on assessing the emergent success in this
endangered species.
Abstract: Trihalomethanes (THMs) were among the first
disinfection byproducts to be discovered in chlorinated water. The
substances form during a reaction between chlorine and organic
matter in the water. Trihalomethanes are suspected to have negative
effects on birth such as, low birth weight, intrauterine growth
retardation in term births, as well as gestational age and preterm
delivery. There are also some evidences showing these by-products to
be mutagenic and carcinogenic, the greatest amount of evidence being
related to the bladder cancer. However, there exist inconsistencies
regarding such effects of THMs as different studies have provided
different results in this regard. The aim of the present study is to
provide a review of the related researches about the above mentioned
health effects of THMs.
Abstract: The bromination of five selected pharmaceuticals
(metoprolol, naproxen, amoxicillin, hydrochlorotiazide and
phenacetin) in ultrapure water and in three water matrices (a
groundwater, a surface water from a public reservoir and a secondary
effluent from a WWTP) was investigated. The apparent rate
constants for the bromination reaction were determined as a function
of the pH, and the sequence obtained for the reaction rate was
amoxicillin > naproxen >> hydrochlorotiazide ≈ phenacetin ≈
metoprolol. The proposal of a kinetic mechanism, which specifies the
dissociation of bromine and each pharmaceutical according to their
pKa values and the pH allowed the determination of the intrinsic rate
constants for every elementary reaction. The influence of the main
operating conditions (pH, initial bromine dose, and the water matrix)
on the degradation of pharmaceuticals was established. In addition,
the presence of bromide in chlorination experiments was
investigated. The presence of bromide in wastewaters and drinking
waters in the range of 10 to several hundred μg L-1 accelerated
slightly the oxidation of the selected pharmaceuticals during chorine
disinfection.
Abstract: Application of pesticides in the paddy fields has
deleterious effects on non-target organisms including cyanobacteria
which are photosynthesizing and nitrogen fixing micro-organisms
contributing significantly towards soil fertility and crop yield.
Pesticide contamination in the paddy fields has manifested into a
serious global environmental concern. To study the effect of one such
pesticide, three cyanobacterial strains; Anabaena fertilissima,
Aulosira fertilissima and Westiellopsis prolifica were selected for
their stress responses to an Organochlorine insecticide - 6, 7, 8, 9, 10,
10-hexachloro-1, 5, 5a, 6, 9, 9a-hexahydro-6, 9-methano-2, 4, 3-
benzodioxathiepine-3-oxide, with reference to their photosynthesic
pigments-chlorophyll-a and carotenoids as well as accessory
pigments-phycobiliproteins (phycocyanin, allophycocyanin and
phycoerythrin), stress induced biochemical metabolites like
carbohydrates, proteins, amino acids, phenols and enzymes-nitrate
reductase, glutamine synthetase and succinate dehydrogenase. All
the three cyanobacterial strains were adversely affected by the
insecticide doses and inhibition was dose dependent. Reduction in
photosynthetic and accessory pigments, metabolites, nitrogen fixing
and respiratory enzymes of the test organisms were accompanied
with an initial increase in their total protein at lower Organochlorine
doses. On the other hand, increased amount of phenols in all the
insecticide treated concentrations was indicative of stressed activities
of the organisms.