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GVHD: Ths. Trn Cm ThySVTH: Hong Th Thu ThoMSSV: 12031041LHP:
210409501 Mn: K thut phn tch 2 Phn tch formaldehyde trong vi si
Formaldehyde trong vi siIII. Phn tch formaldehide trong vi siNI
DUNG
I. Gii thiu chung v formaldehydeI. Gii thiu chung v
formaldehyde
Formaldehyde l hp cht hu c Tn gi khc nhau nh: formol, methyl
aldehyde, methylene oxide, metanal Cng thcha hc l HCHOTnh cht ca
HCHO
Tn thng phm l foocmalin hay foocmonD tan trong nc , to thnh dung
dch 37%D bay hi, khng mu, mi cay sc, kh ngiL mt cht kh nhit phngI.
Gii thiu chung v formaldehyde
I. Gii thiu chung v formaldehyde
Trong t nhin, formaldehyde c sn trong g, to, c chua, khi ng c,
khi thuc l, khi t g, du v kh ha lng (gaz)L ha cht cng nghip c bn,
rt c i vi sc khe con ngi, l cht c kh nng gy ungth.c dng rng ri
trong cc ngnh cng nghip dt, cht do, trong giy, sn, m phm, keo dn,
thuc n, giy than, mc my photocopy... lm cht kh trng trong nng nghip
v thy sn.
I. Gii thiu chung v formaldehyde
C th con ngi nu tip xc vi formaldehyde trong thi gian di th d hm
lng cao hay thp cng gy ra nhiu tc hi nghim trng cho da v h thng h
hp, cc bnh v bch cu, gy ung th nhiu c quan trong c th, c bit l ung
th ng h hp nh mi, hng, phi,...Formaldehyde l tc nhn gy ra sai lch v
bin d cc nhim sc th, ph n c thai b nhim c th b nh hng n s pht trin
ca bo thai.6 Formaldehyde tn ti trong vi do c s dng trong cng on in
nhum, gi mu v to lin kt ngang chng nhn, chng nm mc. Dng
Formalfehyde dngnha dng chng nhu, p dng cho cc sn phm dt t si thin
nhin nh cotton, t tm... Formaldehyde c nhng vn c s dng trong cng
nghip dt v gi thnh r.II. Formaldehyde trong vi siSTTTn mt hng Hm
lngNhm 1Sn phm dt may dnh cho tr di 36 thng tui30 mg/kgNhm 2Sn phm
dt may tip xc trc tip vi da75 mg/kgNhm 3Sn phm dt may khng tip xc
trc tip vi da300 mg/ kgII. Formaldehyde trong vi siHm lng HCHO cho
php trong vi siV formaldehyde c c tnh ha tan trong nc, nn tt nht
qun o, chn drap, rm mi mua v nn git sch trc khi dng gim nguy c nhim
c (d lng formaldehyde trong cc sn phm dt may gim 60% sau khi git ln
u).
II. Formaldehyde trong vi si
1. Phm vi p dng Tun theo TCVN 7421 - 2: 2004 (ISO 14184-2:
1998). p dng cho tt c cc loi vt liu dt. Xc nh hm lng formaldehyde t
do v thu phn trong khong t 20 mg/kg n 3500 mg/kg.
III. Phn tch formaldehide trong vi si
2. Nguyn tc Formalehyt c chit t mu th vi nc 40 C. Hm lng
formalehyt sau c xc nh bng phng php so mu.
III. Phn tch formaldehide trong vi si
3. Thuc thNc ct hoc nc loi 3 ph hp vi TCVN 4851: 1989 (ISO 3696:
1987). Thuc th axetylaxeton. Dung dch formalehyt, xp x 37 % (W/V
hoc W/W). Dung dch imeon trong etanol
III. Phn tch formaldehide trong vi si
. Thuc th axetylaxeton.ho tan 150 g amon axetat trong khong 800
ml nc (4.1), b sung 3 ml axit axetic bng v 2 ml axetylaxeton, chuyn
hn hp vo bnh nh mc 1000 ml v cho nc (4.1) y n vch mc. Bo qun dung
dch va pha trong chai mu nu.CH THCH 1: Thuc th ny hi ng mu ti sau
12 gi u bo qun. V vy thuc th ny phi c gi 12 gi trc khi s dng. Mc d
vy, thuc th ny cng c th s dng c sau mt khong thi gian bo qun di, t
nht su tun. V nhy ca thuc th c th thay i sau mt khong thi gian di
bo qun, trong trng hp ny phi tin hnh hiu chun hng tun iu chnh cc
thay i nh trn ng cong chun.
124. Quy trnh tin hnhBc 1: Chun b dung dch chunChun b khong 1500
mg/l dung dch formalehyt d tr bng cch ho tan 3,8 ml dung dch
formalehyt trong nc thnh 1 lt
III. Phn tch formaldehide trong vi si
Bc 2: Chun li dung dch chun HCHO Cho mt phn dung dch d tr tc dng
vi natri sunfit d ri chun vi dung dch axit, dng cht ch th
thymolphtalein.Phn ng: III. Phn tch formaldehide trong vi si
HCHO + Na2SO3+ H2O = NaOH + CH2(NaSO3)OHNa2SO3 + H2SO4 = H2O +
Na2SO4 + SO2
III. Phn tch formaldehide trong vi si
Tnh ton nng formalehyt trong dung dch d tr (theo g/ml) theo cng
thc sau:(V1.0,6 .1000) / VTrong : 1ml axit sunfuric 0,01 mol/l tng
ng vi 0,6 mg formalehyt.V1 : Th tch axit sunfuric s dng (theo ml)V:
Th tch dung dch mu (ml)
III. Phn tch formaldehide trong vi si
Bc 3: Chun b dung dch hiu chun (S2)Pha long 10 ml dung dch chun
chun (cha 1,5 mg/ml formalehyt), vi nc thnh 200 ml trong mt bnh nh
mc. Dung dch ny cha 75 mg/l formaldehyde.
III. Phn tch formaldehide trong vi si
Nng tng ng ca formalehyt trong mu th, da trn khi lng ca 1g mu th
x l trong 100 ml nc, s l 100 ln nng chnh xc ca dung dch chun. III.
Phn tch formaldehide trong vi si
Dung dch S2(ml)1251015203040nh mc500Hm lng HCHO tng ng
(g/ml)0,150,30,751,52,2534,56Hm lng HCHO trong mu th
(g/100ml)153075150225300450600CH THCH 3: Vic pha long hai ln ny l
cn thit c cng nng formalehyt trong dung dch hiu chun cng nh trong
dung dch th ca vi. Nu mu vi cha 20 mg/kg formalehyt th chit 1,00 g
mu th bng 100 ml nc; dung dch cha 20 g formalehyt v t suy ra trong
1 ml dung dch th cha 0,2 g formalehyt18Bc 4: Xy dng ng chunng cong
hi quy c dng: y = a + bx. ng cong hi quy ny s c s dng cho tt c cc
php o. Nu mu th cha lng formalehyt ln hn 500 mg/kg th pha long dung
dch mu th.
III. Phn tch formaldehide trong vi si
Lc bnh t nht c 5 pht mt ln. Sau lc dung dch vo mt bnh khc qua
phu lc
ng cht nt v t bnh vo bp cch thu nhit (40 2)C khong (60 5) phtBc
5. Chun b mu th
cho cc mu vn cn vo trong mt bnh tam gic 250 ml c nt v b sung 100
ml nc
Ct mu th thnh cc mu vn, cn khong 1 g III. Phn tch formaldehide
trong vi si
Bc 6: Tin hnh phn tcht cc ng nghim ny vo bp cch thu (40 2)C
trong khong thi gian (30 5) pht v sau nhit phng trong khong (30 5)
pht nas dng my quang ph, cuvet dy 10 mm o hp th i chng vi nc ti bc
sng 412 nm.
Cho 5 ml mu lc vo ng nghim v 5 ml mi dung dch formalehyt chun vo
cc ng khc . Thm 5 ml thuc th axetylaxeton vo mi ng nghim v lc
u.
Cho 5 ml dung dch thuc th axetylaxeton vo ng nghim cha 5 ml nc c
x l theo cng mt cch nh vi thuc th trng. III. Phn tch formaldehide
trong vi si
CH : Mu vng c trng ca dung dch xut hin trong ng nghim, nu trc
tip di nh mt tri trong mt thi gian d b nht mu. Nu phi tr hon ng k
(v d trong 1 h) vic o kt qu t ng nghim sau khi mu xut hin v nu c
nhiu nh sng mt tri th phi bo v cn thn cc ng nghim bng cch bc cc ng
nghim bng tm ph khng c formalehyt. Ngoi ra, mu ny s n nh trong mt
thi gian di (t nht l qua m) v vic o kt qu c th b tr hon, nu cn.
21 Tin hnh t nht hai php th song song Nu c nghi ng v hp th khng
phi do formalehyt m do cc tc nhn mang mu khc c chit ra th tin hnh
mt php th xc nhn, s dng imeonIII. Phn tch formaldehide trong vi
si
Tnh ton v biu th kt quHiu chnh hp th ca mu th nh sau:A = As - Ab
- (Ad)Trong :A l hp th c hiu chnh;As l hp th o c ca mu th;Ab l hp
th o c ca thuc th trng;Ad l hp th o c ca mu th trng (ch trong trng
hp dung dch th b nhim bn hoc b mt mu).
III. Phn tch formaldehide trong vi si
Lng formaldehyde chit ra t mi mu (F) theo mg/kg, c tnh bng cng
thc sau:F= (C x 100) / WTrong :C : nng ca formalehyt trong dung dch
(theo mg/l), W : khi lng ca mu th, tnh bng gam.Tnh gi tr trung bnh
ca hai gi tr o.Nu kt qu tnh c nh hn 20 mg/kg th bo co l "khng pht
hin".
III. Phn tch formaldehide trong vi si
Ti liu tham khoTCVN 7421-1 : 2004 Vt liu dt xc inh formaldehyde
phn 1: formaldehyde t do v thy phn ( phng php chit trong nc).2.
TCVN 7421-2 : 2004 (ISO 14184-2 : 1998) Xut bn ln 1 Vt liu dt - Xc
nh Formaldehyt Phn 2: Formaldehyt gii phng ( Phng php hp th hi
nc).3. TCVN 1748 - 91 (ISO 139: 1973), Vt liu dt - Mi trng chun iu
ho v th.4. TCVN 5783 2009, Vt liu si phng php ly mu5.
http://www.hoahocngaynay.com/vi/phat-trien-ben-vung/an-toan-hoa-chat/355-formandehyde-san-xuat-va-ung-dung.pdf
Cm n c v cc bn lng nghe !L.O.G.O
