R O C Z N IK I G L E B O Z N A W C Z E T. X L II N R 1/2 W A R S Z A W A 1991: 27 — 35
B A R B A R A GWOREK. M AREK BO ROW IAK
MODEL ST U D IE S ON IM M OBILIZATION OF CERTAIN H E A V Y METALS BY SYNTH ETIC ZEOLITE
S oil S cien ce D epartm ent, W arsaw A gricu ltu ral U n iv ersity
INTRO DU CTIO N
In m odern w orld th ere are m any sources of h eavy m etals em m is- sions, w hich h ave been deposited in our environ m en t m ain ly in soil. T his typ e of the environ m en t contam ination still has risen.
To solve the problem m any m ethods w ere proposed m ost of w hich
are very exp en siv e and onerous. One of a n ew possible w a y to achie v e this goal is to use zeolites as ,,recon stitu en t traps” of soils h eavy
m etals [1, 2]. It is w e ll know n that zeolites — prim arily natural
occur in soils [5, 7], now natural and syn th etic m olecular siev es [4] — possess m any in terestin g properties connected w ith their fine defined crystal structure and intracrystallin e cavities. The particular properties e.g. large ion exchan ge and adsorption capacities course that use of zeolites in soil im proves som e properties of soil and at the sam e tim e zeolites act as good traps for the m etals presented in soil. P rac tical m ethods of the use of syn th etic m olecular siev es as the traps in
so ils w ere w orked out [6].
B orowiak [3] studies the dynam ic of changes of h eavy m etals con ten t in soils in a system ,,zeolite — so il”. It w as found th e dynam ic depends on properties of the soils. More detail m odel studies on this problem w ere suggested.
There is just th e purpose of the p resent paper to describe resu lts of th e m odel studies on syn th etic zeolite type 4A com peted for h eavy m etals ions (Zn(II), Cu(II), Pb(II) w ith som e m ineral soils com ponents.
M A TE R IA L S A N D M ETHODS
S ystem s: th e zeolite — a m odel m ineral soil com ponent w ere stu
28 В. G w o r e k , М. B o r o w ia k
5 g of the zeolite w ere placed in quartz beaker. N e x t the solid m ixtu re w as covered by a solution of th e n itrates w ith pH = 5 (1 m m up the solid phase). A fter m ix in g 3 drops of chlorophorm w ere added and
the beaker w as shut close. Each stu d ied system contained 1 2 0 0 0 ppm
Zn(II), 3000 ppm Cu(II) and 6000 ppm Pb(II). A conservation tim e of th e system s w as one, s ix and tw e lv e m onths in a dark place and a room tem perature. Each exp erim en t w as four tim e repeated.
A fter and of the exp erim en t the solid phase w as separated from the solution, dried in room tem perature and n ex t th e zeolite phase w as separated from th e com ponent phase.
For the m etals extraction s from th e zeolite after th e exp erim en t
th e follow in g m edia w ere used: 1) re-d estilla ted w ater, 2) aqueous
solution 1 M CH3COONH4 (pH = 7,2), 3) aqueous solution 0,1 M HC1,
4) aqueous solution 20% HC1.
To extract the m etals a sam ple of zeolite w as ca n secu tively treated w ith 1., 2., 3., and 4 m edia during 24 hours. The A S A technique w as used for an alysis of the m etals in solutions, Zn(II) and Cu(II) w ere analyzed in th e aqueous solutions, and Pb(II) — after extractin g from th e solution s to organic phase.
R ESU L TS
Zinc. The results of the zinc extraction s from th e zeolites after
the exp erim en ts are p resented in Table 1. A total content of zinc in th e zeolites w ere calcu lated as a sum of th e four con secutive ex tra c tions and an am ount of exchan geab le zinc in th e zeolites, available in th e natural soil conditions for an ion exchan ge and for plant w as
assum ed to be a sum of extracted w ith H20 , 1 M CH3COONH4, and
0,1 M HC1.
The b iggest total content of zinc w as found in th e exp erim en ts
w ith quartz sand (92,35— 99,06° / 0 of added zinc, depends on th e con
servation tim e), the sam e order w as found for F e2 0 3 X nH20 after
12 m onths (98,54%)) starting from 66,43% after 1 m onth. In the p re
sent of k aolin it the content w as found to be low er (46,43— 56,65°/1.)
but still m uch m ore higher a s com pare w ith b en ton ite ( 0 ,2 8— 0,91%)
and b eid elite (1,65— 1,96%). T hese latter resu lts probably m ay be e x plained taking into account large sorption capacités of b en ton ite and beid elite v/hich are about 7— 26 tim es greater than that of kaolinite. The affin ity of zinc for th e m inerals m ay also p lay a role.
A percent portion of exchan geab le zinc exp ressed as a ratio of the am ount and the total content of zinc in th e zeolite w as found to be greatest in th e p resent of k aolin ite (29,27— 38,96%) and lo w est in the
T a b e l a 1
R esults of zin c e x tra ctio n s
Item
Tim e
Im onthsl
1
The ex tra ctin g m edia, ppm
2 3 4 2i,2,,.4 ppm Ста Ex*> Vo Quartz 1 0,6 1680 516 10000 11196,6 92,85 10,69 sand 6 0,9 1900 1820 8200 11920,9 98,89 31,21 12 0,8 1440 2000 8500 11940,8 99,06 28,82 K aolinite 1 0,6 1680 502 3420 5602,6 46,43 38,96 6 0,6 1640 552 4660 68,52,6 56,65 32,00 12 0,9 1280 656 4680 6616,9 54,69 29,27 B entonite 1 0,8 8,6 10 144 163,4 0,91 11,82 6 1,2 6,7 5,2 74 87,1 0,28 15,04 12 1,0 8,9 6,2 107 123,0 0,57 13,01 B eid elite 1 0,6 26,0 66 160 252,6 1,65 31,95 6 0,6 21,2 48 220 289,8 1,96 31,73 Fe20«} X nH 20 1 1,2 512 312 7200 8025,2 66,43 10,28 6 1,8 528 363 10200 1109,8 91,98 8,05 12 1,2 466 412 11000 11879,2 98,54 7,40 Z eolite before
exp erim en ts traces 0,4 1,4 52,7 54,5
• CT — (S i,2,3,4 — Szeoiitć) • 100 / am ount o f added zin c.
3 0 В. G w o r e k , М. B o r o w ia k
Copper. The results of the copper extraction from the zeolites after
the exp erim en ts are p resented in Table 2 . The total content of copper
in the zeolites w as found to decrease in order: quartz sand (72,28—
77,33°/n); k aolin ite (39,47— 43,77%); F e203 X nH20 (29,52— 36,99%); b e-
id elite (0,37— 0,47%) and b en ton ite (0,17— 0,51%).
The percent portion of exchan geab le copper w as found to be grea test in the present of k aolin ite (44,33— 47,51%) and low est in present of hydrated iron (III) oxid e (7,96— 15,49%).
Lead. The results of the lead ex traction from th e zeolites a fter
the exp erim en ts are presented in Table 3. A ll of the lead added to the quartz sand — zeolite system w as found to be in the zeolite after 1 m onth (the total content 99,27%). In the p resent of k aolin ite the content w as 63,45— 75,08% depends on the conservation tim e. O nly a sm all content of lead w as in zeolite in p resent of bentonite, b eid e-
lite and F e203 X nH20 : 1,17— 2,92%; 0,72— 0,75%; 0,42— 1,00%, respec
tiv ely .
The percent portion of exchan geab le lead w as found to change from 10,12% to 55,77% depends on the m ineral com ponents and tim e.
D ISC U SSIO N
There are m any typ ies of possible interactions b etw een zeolite and soil in any zeo lite-soil system but it seem s reasonable to assum e that m ost of the interactions occur throught a natural aqueous solution in a w et soil. The solution m ay be in an eq u ilib rium w ith the exch an geable ions of h eavy m etals there are on m ineral and organic com p onents of soil. T he interactions b etw een th e natural com ponent of soil as also b etw een the natural com ponent and zeolite m ay change this equilibrium state replaced ions on sites m ore th erm o dynam ic favourable. For the sam e reason in zeolite interacted w ith a solution salt occlusion or im bibition of h ea vy m etals com pounds
are possible too [4]. W ater and sm all organic com pounds w ould
be adsorbed v ery strong by zeolites also. The latter adsorption m ay be elim in ate if a zeolite w ith sm all w in dow s w ill be used.
In the p resent stu d ies a first step w as made to m odel the com pli cated system zeolite-soil. The m odels used in our studies represent „zeolite-aq ueous solution s com ponent of so il” system as sim ple as possible (e.g., the solution s contains on ly four typ ies of ions, three m etals ions and nitrate ion), a com ponent of soil in the begining of exp erim en ts did not contain contam inations of h eavy m etals studied it w as used the zeolite 4A w ith narrow w indow s (about 4A, etc.). To m odel the natural conditions at the end of any exp erim en t no w ash and only drying w ere used. It m eans that the obtained total content
T a b l e 2 R esu lts of copper ex tra ctio n s
Tim e The ex tra ctin g m edia, ppm
Item [m onths] 1 2 3 4 ^ 1.2,8,4 ppm CTa i E x ь % Quartz 1 0,3 566 253 1360 2179,3 72,28 37,59 sand 6 0,8 357 451 1540 2348,8 77,93 19,20 12 tr 279 486 1460 2225,0 73,81 34,38 K aolinite 1 tr 390 197 737 1324,0 43,77 44,33 6 tr 322 205 684 1211,0 40,01 43,52 12 tr 309 260 626 1195,0 39,47 47,52 B entonite 1 tr 4,4 1,8 19,9 26,1 0,51 23,75 6 tr 2,9 1,0 12,0 15,9 0,17 24,53 12 tr 4,0 1,1 17,9 23,0 0,41 22,17 B eid elite 1 tr. 4,6 4,4 12,8 21,8 0,37 41,28 G tr 6,0 3,0 15,8 24,8 0,47 36,29 F e20 3xn H 20 1 0,8 36,9 33,7 825 896,4 29,52 7,96 6 0,9 73,2 61.0 870 1005,1 33,14 13,44 Z eolite before 12 1,4 74,0 98,2 947 1120,6 36,99 15,49 exp erim en ts tr. tr. tr. 11,0 11,0 — — •*b S e e T a b le 1, tr = tr a c e.
'Г a b l e :> R esults of lead ex tra ctio n s
Tim e The e x tra ctin g m edia, ppm
Item 1 2 3 4 1.2.8»4 C Ta E x 1’ [m onths] ppm % Quartz 1 0,8 958 781 4318 5957,8 99,27 27,53 sand 6 0,8 954 1586 3492 6033,8 100 42,13 12 0,8 922 1730 3385 6037,8 100 43,94 K aolinite 1 0,8 918 888 2019 3825,8 63,45 47,23 6 0,8 1237 949 2338 5423,8 75,08 48,33 12 0,8 1290 1138 1776 4205,8 69,77 57,77 B entonite 1 tr. tr. 20 69 89 1,17 22,47 6 tr. tr. 23 118 141 2,03 16,31 12 tr. tr. 25 169 194 2,92 12,87 B eidelite 1 tr. 6 20 36 62 0,72 41,93 6 tr. 6 18 40 64 0,75 37,50 F e20 8x H 20 1 tr. 8 tr. 50 58 0,65 13,79 6 tr. 8 tr. 71 79 1,00 10,12 12 tr. 6 tr. 38 44 0,42 13,64 Z eolite before exp erim en ts tr. tr. tr. 19 19 — — »•b S e e T a b le 1.
I m m o b i l i z a t i o n of h e a v y m e t a l s b y ze o lite 33
of h ea v y m etals in zeolites resu lts not o n ly from the studied in terac tions in the system but from th e drying operation, also.
The m odel stu d ies p resented in this paper illu stra te th at an effec tiv en ess of action o f th e zeolite as h eavy m etals trap is depend on typ e of th e com ponent of soil and of m etal. It is easy for th e zeolite to com pete for h ea v y m etals ions w ith quartz sand and. — less — w ith k aolin ite. The largest effect w as found w ith quartz sand for lead
(about 1 0 0 % added lead w as trapped v er y q uick ly by zeolite), a little
low er — for zinc (95°/o) and for copper (75°/o). O nly a little effect w as ob served for b en ton ite and beidelite. From this point of v ie w it seem s not reasonable to exp ect th is typ e of zeolite m ay be a good trap of th e m etals in h ea v y soils. On th e other hand, u sing th e ty p e of zeolite in soil from K atow ice (w ith v ery large contam ination of h ea v y m e tals) about 80°/o of lead w as rem oved from th e soil after th ree m onths [1]. This problem need m ore detail studies.
It seem s that about 78% of zinc, 70% of copper and 6 8% o f lead
trapped in zeolite should be not available in natural conditions for plants, as indicate th e resu lts of percent portion o f exchan geab le m e tals in zeolite.
R EFEREN CES
[1J B o r o w i a k M., G ó r n y M., K o t В., L e w a n d o w s k i W. Stu d y on d istrib u tion of h ea v y m eta ls in an th rop ogen ic so il-z e o lite system s. Prep. Pap. of Sc. M eeting PTC hem ., K a to w ice 1983.
[2] B o r o w i a k M., C z a r n o w s k a K., L e w a n d o w s k i W., K o t В. S tudy on d ynam ic of ch an ges of h ea v y m eta ls co n ten ts in a n th rop ogen ic soils in p resen t of zeolites. I l l Nat. Conf. „In flu en ce of co n tam in ation s of trace m eta ls on n atu ral con d ition s of a g ricu ltu re”. P u la w y 1985.
[3] B o r o w i a k M. , C z a r n o w s k a K., L e w a n d o w s k i W., K o t В. S tu d y on d yn am ic of ch an ges o f h e a v y m eta ls con ten ts in an th rop ogen ic soils in p resen t of zeolites. Rocz. G lebozn. 1986, 37 (4), 67.
[4] B r e c k D. W. Z eolite m olecu lar siev es. W illey, N ew Y ork 1974.
[5] B r o g o w s k i Z, The p o ssib ility of zeo lites occurrence in th e soils of P oland. Zesz. Prob. Post. N auk Rol. 1983, 220.
[6] G w o r e k В., B o r o w i a k M. Zgt. Pat. No 283821 (RP). 1990.
[7 ] S a n d y L. B., M u m p t o n F. A. N atu ral zeolites. O ccurrence, p roperties, uses. P ergam on Press, N e w Y ork 1978.
34 В. G w o r e k , М. B o r o w ia k Б. Гворек, М. Б оровяк М ОДЕЛЬН Ы Е И СС Л ЕД О ВАН И Я ПО С О РБЦ И И Т Я Ж Е Л Ы Х М ЕТАЛЛОВ СИ Н Т ЕТИ Ч ЕС К И М И ЗЕО Л И Т А М И К а ф ед р а почвоведени я В арш авской сел ьск охозя й ств ен н ой академ ии Р е з ю м е П роводились м одельн ы е исследован и я по сорбции т я ж ел ы х м еталлов (Pb, Zn и Cu) синтетическим и зеолитам и в едини чны х си стем ах с кварцевы м песком (стекольны м), каолинитом, бейделитом , бентонитом и гидратированной окисью ж е л е за . У к азанны е минеральны е ком поненты см еш ивали с зеолитом в весовом соотнош ении 20 : 1 и зал и в али раствором нитратов Pb (II, Zn (II) и Cu (II) в к ол и ч ествах соответственно 6000, 12000 и 3000 мг/кг сухого вещ ества минерального компонента. И н кубация системы п р одол ж ал ась 1, 6 и 12 месяцев. В систем е з е о л и т — кварцевы й песок иссл едуем ы й материал сорбировал 99,27 — 100°/о прибавленного свинца, 92,35 — 99,06% цинка и 72,28 — 77,89% меди; в систем е с каолинитом соответственно 63,45— 75,08 Pb, 46,43 — 56,65% Zn и 39,47 — 43,77% Cu; в системе с бентонитом соответственно 1,17 — 2,92% Pb, 0,28 — 0,91 % Zn и 0,17— 0,51% Cu; в систем е в бейделитом соответственно 0,72 — 0,75% Pb, 1,65 — 1,96% Zn и 0,37 — 0,47% Cu; в систем е с гидрати рован ной окисью ж е л е з а соответственно 0,65 — 1,00% Pb, 66,43 — 98,54% Zn и 29,52 — 36.99% Cu. В . G W O R E K , М B O R O W IA K
MODELOWE B A D A N IA N A D SO R PC JĄ M ETALI CIĘŻKICH PRZEZ SY N TETY C ZN E ZEOLITY
K a te d r a G le b o z n a w s tw a SG G W w W a r sz a w ie
S t r e s z c z e n i e
P rzeprow adzono m o d elo w e badania nad sorpcją m eta li ciężk ich (Pb, Zn i Cu) przez sy n tety czn e zeo lity w u k ład ach p ojed yn czych z p ia sk iem k w arcow ym (szklarskim ), k aolin item , b eid elitem , b en to n item oraz u w o d n io n y m tlen k iem ż e lazow ym . W ym ien ion e k om p on en ty m in era ln e zm ieszano z zeo litem w stosunku v/agow ym 20 : 1 i zalano roztw orem azotan ów Pb(II), Zn(II) i Cu(II) w ilości od p ow ied n io 6000, 12000 i 3000 m g/k g suchej m asy kom p on en ta m in eraln ego. In k u bacja układu trw a ła 1, 6 i 12 m iesięcy.
W u kładzie zeolit — p ia sek k w a rco w y b ad an y m in erał zasorb ow ał 99,27— 100% dodanego ołow iu , 92,35— 99,06% cynku i 72,28— 77,93% m iedzi; w u k ład zie z k a o lin item o d p ow ied n io 63,45— 75,08% Pb, 46,43— 56,65% Zn i 39,47— 43,77% Cu; w u k ład zie z b en to n item o d p ow ied n io 1,17— 2,92% Pb, 0,28— 0,91% Zn i 0,17— 0,51% Cu; w u k ład zie z b eid elitem o d p ow ied n io 0,72— 0,75% Pb, 1,65— 1,96% Zn i 0,37—
0,47% Cu; w u k ład zie z u w o d n io n y m tlen k iem żelaza od p ow ied n io 0 65— 1 00% Pb, 66,43— 98,54% Zn i 29,52— 36,99% Cu. D r B. G w o r e k P r a c a w p ł y n ę ł a d o r e d a k c j i w l i p c u 1990 r K a t e d r a G l e b o z n a w s t w a S G G W - A R w W a r s z a w i e 02-528 W a r s z a w a , R a k o w i e c k a 26/30 _________________ I m m o b i li z a ti o n of h e a v y m e t a l s b y z e o lite 3 5 D r M. B o r o w i a k I n d u s t r i a l C h e m i s t r y R e s e a r c h I n s t i t u t e D e p a r t m e n t o f I n d u s t r i a l C a t a l y s i s 01-793 W a r s z a w a , R y d y g i e r a 8
