高分求工业设计<Industrial Design>英语文献

高分求工业设计<Industrial Design>英语文献

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第17 卷第4 期 皮 革 科 学 与 工 程 Vol117 ,No14
2007 年8 月L EATHER SCIENCE AND ENGINEERING Aug1 2007
Artical ID :1004 - 7964 (2007) 04 - 0003 - 06
Received Date :2007205221
3 P. Mokrejs :Corresponding author. Phone N°: + 420 57 603 1230 ;Fax N°: + 420 57 603 1563 ;e2mail :mokrejs @f t . utb. c2
Recycling Technology for Waste Tanning Liquors
P. Mok rejs1 3
, D. J anacova2 ,M. Mladek1 , K. Kolomaz nik2 , F. L angmaier1 ,V . V asek2
(1. Tomas B ata University , Faculty of Technology , Department of Protein and Leather , nam.
TGM 275 , 762 72 Zlin, The Czech Republic ;2. Tomas B ata University , Faculty of
A p plied Inf ormatics , Institute of Processing Cont rol and A p plied Computer Science ,
N ad S t ranemi 4511 , 760 05 Zlin, The Czech Republic)
Abstract :Tannery belongs to typical indust rial branches which during t he technological process
p roduce considerable quantities of liquid and solid wastes cont ributing to polluting t he environ2
ment . The presented work describes dechromation of waste tanning liquor utilising chrome sludge
p roduced t hrough enzymatic hydrolysis of chrome2tanned leat her wastes. The principle of dechro2
mation consist s in sorption of chrome f rom waste liquor af ter tanning to chrome sludge. Recy2
cling technology is characterised by an almost 99 % efficiency , simplicity and low investment re2
quirement s.
Key words :solid waste ;liquid waste ;chrome sludge ;waste tanning liquor ;chrome recovery
CLC number :X 794 Document code :A
鞣制废液的循环技术
摘 要:制革属于典型的工业分支,制革工业中会产生大量的污染环境的废液和废固。该论文利用铬鞣革废物的
酶法水解用铬污泥除去鞣制废液中的铬。除去铬的原理是鞣后的铬污泥从废液中吸收铬。该循环技术回收率可
达99 % ,操作简单、成本低廉。
关键词:固体废弃物;液体废弃物;铬污泥;鞣制废液;铬回收
1 INTRODUCTION
The tanning indust ry p rocesses wastes of the
meat indust ry , raw hides , and t ransforms t hem
t hrough chemical , chemico2p hysical and mechani2
cal processes into leather s. During t he technologi2
cal process , solid and liquid wastes arise which ,
particularly as a consequence of t he cont rover sial
chrome t hey contain , burden the environment .
Processing one met ric ton of raw hide produces ap2
prox. 200 kg finished leat her . About 30 , 000 kg
wastewaters arise through processing and more
t han 70 % chrome passes into liquid and solid
wastes [1 ] .
In classic tanning , approx. 40 % chrome (t he
starting charge of 15 - 17 kg Cr / t ) remains in
leat her , 26 % - 30 % chrome passes into solid
wastes and 30 % - 34 % chrome remains in liquid
wastes. In t he tanning of hides using technological
procedures ensuring high removal of chrome com2
pounds by white hide , 54 % - 57 % chrome remains
© 1994-2008 China Academic Journal Electronic Publishing House. All rights reserved. http://www.cnki.net
in leat her , 31 % - 38 % chrome passes into solid
wastes and 5 % - 15 % remains in liquid wastes [2 ] .
For modifying t he tanning process , organic acids ,
e. g. are used , which cont ribute to improving the
removal of chrome ions.
1. 1 Liquid waste
Manufacture of chrome2tanned leat hers pro2
duces 115 - 2 times quantities of wastewater s t han
manufact ure of vegetable2tanned leat her s [3 ] . Los2
ses of chrome compounds in waste tanning liquor s
may be prevented in several ways. The simplest
approach is the direct recycling method consisting
in re2using exhausted liquor in t he tanning process.
The main shortcoming of t his method is a negative
effect of salt s and other contaminating substances
on quality of finished leather . Af ter being recycled
several times , wastewater has to be discharged into
sewage [4 ] . Anot her potential met hod is indirect
recycling , in which chrome is obtained f rom ex2
hausted sludge t hrough precipitation using a suit2
able alkaline agent , e. g. sodium hydroxide , sodi2
um carbonate , sodium hydrogen carbonate , mag2
nesium oxide , calcium sulp hate , calcium hydroxide
[5 ] . A f urt her met hod consist s in employing elabo2
rate techniques , e. g. elect ro2dialysis , membrane
separation , ion exchangers , wit h which chrome
may be separated f rom ot her salt s contained in ex2
hausted sludge. Chrome thus obtained is character2
ised by much higher p urity than that obtained
t hrough indirect recycling. Disadvantages are a
high cost and limited po ssibilities of applying t hese
demanding technologies in tanning factories [ 4 ] .
Unutilised chrome in liquid wastes , apart
f rom significant economic losses for tanneries , al so
poses great hazard for t he environment and for
man. The most stable and most important oxida2
tion state is Cr ( III) . Compounds of Cr (VI) occur
in t he form of chromates and dichromates and ex2
hibit quite st rong oxidative properties [6 ] .
Chrome is found in liquid tanning wastes in it s
t rivalent form , there exist s , however , potential
danger of it s oxidising to hexavalent compounds ,
particularly when t reating groundwater s to drink2
ing waters. Hexavalent compounds , when com2
bined wit h calcium or magnesium ions , are st rong2
ly carcinogenic[7 , 8 ] .
An extensive research exploring negative
effect s of tanning wastewaters f rom local tanneries
on t he adjacent ecosystem was conducted in Indi2
a[9 ] . Highest level s of chrome contained in soil
were found in t he vicinity of tanneries , at approx.
60 g/ kg. Highest chrome accumulation was ob2
served in cauliflower stalks (72 mg/ kg) in locali2
ties near tanneries. In st udies investigating Cr ac2
cumulation in fish organs it was found t hat most
chrome accumulates in t he liver (approx. 22 mg/
kg) and least in muscles (approx. 1 mg/ kg) . The
po ssible t ransfer of hazardous Cr doses into t he
food chain and consequently to human beings is
t hus quite obvious.
112 Sol id waste
Tannery processing al so produces a considera2
ble quantity of solid chrome2tanned wastes which
present a significant problem due to t heir chrome
content . The problem of solid wastes has been
solved so far by land filling which , of course , be2
side ever increasing land filling co st s al so brings
t he danger of chrome escaping into t he ecosystem.
Due to t heir containing a sizeable proportion of
protein material , solid tanned wastes started to be
processed. Enzymatic hydrolysis has being em2
ployed to considerable extent in latest year s , wit h
it s particular advantages being mild reaction condi2
tions and economic cost2effectiveness [10 , 11 ] . The
main product of enzymatic hydrolysis is collagen
hydrolysate , whose application possibilities are
broad , e. g. as feed additive , nit rogenous fertili2
ser , raw material for preparing adhesives , corro2
sion inhibitor s , etc. The remaining waste product
af ter enzymatic hydrolysis (chrome sludge) has not
yet found lucrative application. It s employment ,
due to chrome content , has not been much adopted
for preparing combined tanning bat hs.
Subject of the presented work is potential use
4 皮革科学与工程 第17 卷
© 1994-2008 China Academic Journal Electronic Publishing House. All rights reserved. http://www.cnki.net
of t he waste product af ter enzymatic hydrolysis of
chrome2tanned solid wastes (chrome sludge) for i2
solating chrome compounds f rom waste tanning
liquor s.
2 MATERIALS AND METHODS
Solid was determined according to ISO 4684
[12 ] , ash according to ISO 4047 : 1998[13 ] , nit rogen
according to ISO 5397 : 1984 [14 ] , Cr2 O3 according
to ISO 5398 [ 15 ] , Cr according to ISO 9174 : 1998
[16 ] and Mg according to ASTM D511203 [ 17 ] .
Chrome sludge is a waste product of enzymatic
hydrolysis of chrome2tanned solid waste and it s
composition is given in Tab. 1. Typical composi2
tion of chrome2tanned solid waste is given in Tab.
2.
Tab11 Composition of chrome sludge1)
表1 铬污泥成份
Parameter Value
TS/ % 1614
Ash/ % 3410
N / % 114
Cr2O3 / % 1215
MgO / % =.=~~你做毕业设计用啊??不是有专门的工业设计中英文双语的书么~