R O C Z N I K I G L E B O Z N A W C Z E , T . X I X , D O D A T E K , W A R S Z A W A 1968
Soil Chemistry
A L IN A K A B A T A -P E N D IA S
THE SO R PTIO N OF TRACE ELEM ENTS BY SO IL-FO R M IN G M IN ERA LS
T race E lem en t L aboratory, In stitu te of S o il S cien ce and C u ltiv a tio n of P lan ts, P u ła w y
IN T R O D U C TIO N
Since th e firs t recognition of pro b lem of th e tra c e elem ent deficiency and th e use of trace elem ents as fertiliz e rs, th e re have been nu m ero u s studies on th e fix atio n of h eav y m eta l cations by soils. The ab ility of soil-form ing m in erals to accu m u late exch an g eable tra c e elem ents from v e ry d ilu te solution is sig n ifican t from th e sta n d p o in t of p la n t n u tritio n . T h ere are g re a t d ifferen ces b etw een th e ad sorp tion of p a rtic u la r ions by various m in erals. S ev eral a u th o rs [1, 5, 6, 14] have stu d ied in m ore d e ta il th e reactio n s of re ta in tra c e elem en ts w ith soil clays an d some p u re m in erals and have show n th a t th e ir n a tu re is connected w ith specific exchange reactio n s involving fo rm atio n of com plex m eta l ions an d th e p rec ip ita tio n of the m etals w ith in th e clay stru c tu re .
T he fix atio n a b ility of th e so il-form ing m in erals is th u s of in te re s t as a p rin c ip al facto r d ete rm in ig th e m ic ro n u trie n t su p p ly to th e p lan ts. This stu d y w as designed to com pare th e sorption of c e rtain tra c e elem ents by th e m ain soil m inerals.
M A TE R IA L S A N D M ETH O D S
The sam ples of th e m in erals w ere, in gen eral, obtain ed fro m geological deposits, as is in d icated in Tab. 1. The sam ples w ere g ro u n d (if necessary) an d < 2 in fra c tio n w as se p ara te d fro m them . The X -ra y d iffra c tio n id en tific a tio n w as m ade for each m in e ral in o rd er to estab lish its p u rity . The
56 A. K a b a ta -P e n d ia s
m in e ral com position of each sam ple is given in Tab. 1. The m in erals of th e illite and m o n tm o rillo n ite groups w ere th e m ost im pure, the im p u ri ties w ere q u a rtz an d k ao lin ite (Figs 1 and 2). T he X -ra y curves show th a t illite-B and illite-C contain sm aller am o un ts of im p u rities th a n illite -A and th a t m o n tm o rillo nite-B (from Poland) d iffers in its m ineralo gical s tru c tu re fro m th e m on tm o rillo n ite-A (W yom ing bentonite) and contains less q u artz.
T a b l e 1 Some d e s c r i p t i v e data f o r the m in era l samples
Mineral Or igi n CEC
m . e . /1 0 0 g Average c a t i o n d i s p l a c e d m . e . / 100 g Mineralogy o f f r a c t i o n
Quartz Poland 6 . 5 3 3 . 4 pure
A l b i t e Poland 6 .5 3 1 . 6 pure
O rto cl a ee Poland 7-59 2 . 0 pure
O li v in e Norway* 1 2 .0 0 4 . 7 01, Q-trace
Muscovite Poland 1 5 .7 5 1 0 . 7 pure
B i o t i t e Poland 19. 25 1 0 . 1 pure, s l i g h t l y a l t e r e d I l l i t e - A A u s t r a l i a * * 3 7 . 4 5 1 1 . 0 Q, 11 ( F i g . l ) I l l i t e - B USA, I l l i n o i s * * * 17 .7 7 1 0 . 6 Q, I I , Kl, Ch, D ( F i g . l ) I l l i t e - C A u s t r a l i a , s o i l c la y * * 3 9 . 2 0 1 7 . 1 4, 11, K l - t r a c e ( F i g . l ) M on tm o ri ll on ite -A Poland, b e nt o ni te ** ** 98 . 7 0 9 . 4 Mt i F i g . 2 ) M o n tm o r il lo n it e -B USA,Wyoming b e n t o n it e * * * 9 7 . 6 0 4 0 . 0 Mt, Q- trace ( F i g . 2) K a o l i n i t e England, Co rnv ali s I 2 1 . 7 0 3 . 3 pure
Some m in era l samples were ob ta in e d to the c o u r tu e s y , as f o l l o w s : * Dr G.Semb, Vo lle bek k, ** Dr K. Norrish and Dr K . G . T i l l e r , A d e la id e , *** Dr M.M.Mortland, East L ansing, Mich. **** Dr M.Kac-Kaccas, Puławy
Key to mi neralogy: 01- o l i v i n e , $ - qu ar tz , II - i l l i t e , Kl - k a o l i n i t e , Ch - 1 4 . 2 A m i n e r a l s , not determined, D - do lo m it e , Mt - m o n tm o r il lo n it e
A ll e x p e rim e n ts w ere c a rrie d out w ith one low co n cen tratio n of each of th e heav y m etals, using Ca2+ sa tu ra te d m in e ral suspensions as sug gested by H o d g s o n [3] a nd T i l l e r et al. [14]. T he ratio of clay to w a te r w as 1:25, pH of suspensions w as a d ju ste d e x a ctly to 6. A ll tra c e elem ents w ere added in th e a m o u n t of 30 ^g/g for Co, Cu, Zn, and Ni, and in the am o u n t of 1500 ^g/g for Mn. A ll reactio n s w ere c a rrie d out in th e presence of 0.1 N CaC l2 for 20 h o u rs w ith continuous ag itatio n at 21°C. A fter th e tra c e elem ent sa tu ra tio n all clay sam ples w ere cen trifu g ed , w ith sev eral w a te r w ashing and air d ried. The m in erals w ere e x tra c te d by T am m ’s solution (12.608 g oxalic acid and 24.84 g am m onium o x alate per 1 lite r H 20 ; pH 3.2), for 1 hour. T he m in e ral to solution ratio w as 1:50.
The in itia l co n ten t of tra c e elem en ts in m in erals and th e co n ten t a fte r tre a tm e n ts (satu ratio n an d extractio n ) w as d e te rm in e d by spectrop h oto- m etric m ethods [8]. In all solutions o b tain ed a fte r m in e ral sa tu ra tio n and
The sorp tion of tra ce elem en ts 57
Degrees ZQ Си Ha
Fig. 1. X -r a y d iffra ctio n p attern s for th e fra ctio n s < 2 ill sep arated from illite -c la y s
15,2
D egrees 2 в Си К a
Fig. 2. X -r a y d iffra ctio n p attern s for th e fra ctio n s < 2 ц sep arated from b en to n ites
e x tra ctio n th e c o n ten t of Si, Al, Fe, Mg, К and Na w as determ in ed . C ation ex change capacity (CEC) w as m easu red by N H 4 sa tu ra tio n according to m etho d of M a c k e n z i e [12].
R E SU L T S A N D D IS C U S S IO N
P rev io u s w ork [10, 11] and o th er d a ta [2, 13, 14] have show n th a t soil colloids p a rtic ip a tin g m ain ly in th e reactio n s of ion sorption consist not only of clay m in erals and organic m a tte r b u t also of some p rim a ry m
ine-58 A. K a b a ta -P e n d ia s
rals. The com parison of th e ab ility of th e com m on soil-form ing m in erals to fix tra c e elem ents u n d e r th e sam e conditions could rev e a l th e degree of th e ir co n trib u tio n to these reactions. Since calcium is th e d o m in ant ion on th e exchange com plex of m ost a g ric u ltu ra l soils, the exchange reaction s th a t took place w ith trace elem en ts absorbed on the calcium s a tu ra te d ex ch angers should be v e ry sim ilar to those w hich tak e place in soils in th e field.
C o b a l t . The d ifferen ces in re te n tio n and rem oval of cobalt b etw een m in erals as illu s tra te d by th e d a ta given in Tab. 2, show a g rea t v a ria tio n in th e am o u n t of th is elem en t sorbed in th e presence of 0.1 N CaC l2. The p ercen tag e re te n tio n for all m in erals varies from 4 to 100 p er cent (w hich corresponds ap p ro x im ate ly to th e values w hen expressed as m.e./100 g). The sm allest sorption of cobalt (less th a n 10 m.e./100 g) is by q u a rtz , feld sp ars, kao lin ite and illite-A . Also T i l l e r et al. [14] has in d icated th a t th e fix atio n of cobalt by kao lin ite, q u a rtz an d some o th er soil m in erals w as of th e sam e order. It m ay in d icate th a t th is reactio n is associated w ith th e e x te rn a l p lan e r su rfaces r a th e r th a n w ith in te rn a l ones. S im ilar suggestions have been given by H o d g s o n a nd T i l l e r [4] from th e ir stu d y on th e location of bound cobalt on verm iculite.
The cobalt fix atio n by the m in erals of th e illite and m o n tm o rillo n ite groups is not uniform . The differences are due to th e im p u ritie s (e.g. th e cobalt re te n tio n by illite decreases w ith th e increases of th e ir q u a rtz con te n t (Fig. 1), as w ell as to the v a ria tio n in chem ical com position (Tab. 2). T he am o u n ts of m ajo r cations displaced are d iffe re n t for illites an d m o n tm orillo nites and rev eal a k in d of rela tio n b etw een M g2+ and K + d isplacem en t and th e cobalt re te n tio n (Tab. 2). H o d g s o n et al. [5] has assum ed th a t cobalt e n te rs into bond form atio n m ore re a d ily w ith sites occupied by M g2+ th a n w ith those occupied by H 4'.
The cobalt sorption by m uscovite and biotite is of th e sam e o rd er as sorption by illites and m o n tm o rillo nites. O livine, on th e o th er han d, fix ed the h ighest am ou n t of cobalt. It shows cle a rly th a t the reactio n of cobalt so rp tio n is not only due to th e tru e exchange reaction. This is co nfirm ed also by th e re te n tio n of cobalt in excess of th e cation exchange cap acity (CEC) for som e m in e rals (Fig. 3). H o 1 d r i d g e (6) has o b tain ed sim ilar evidence for th e fo rm atio n of com plex m etal ions involved in th e so rp tio n of h eav y m etals by koalinite. M uch e a rlie r H o d g s o n [3] d istin q u ish ed tw o form s of bou nd cobalt, th e exchang eable chem i- sorption and nonexch angeab le, u n d efin ed stro n g fix atio n by m o n tm o rill onite.
T a b l e 2 R e te n ti on and removal of c o b a lt at 30 ppm ad d it io n Mineral Content before treatment ppm Amount r e t a in e d ppm percentage r e t e n t i o n Amount s o l u b l e ppm Per centage removal Cation d i s p la c e d (mg/g) of r e t a in e d amount o f t o t a l co nte nt S i 4+ Al3+ xlOOO Fe^+ xlOO Mg2* r Na+ T o ta l Quertz 0 . 1 1 . 1 3 . 7 0 . 6 34 30 0 . 2 8 1.23 1 . 0 0 0 . 0 3 0.0 7 0 . 0 5 0 . 4 4 A lb it e 0 . 1 2 . 6 8 . 7 0 . 3 12 11 0 .1 8 1.23 1. 7 5 0 . 0 5 0 .0 5 0 .2 8 0 . 5 8 Or to cl a se 0.4 0 . 7 2.3 0 . 2 29 13 0 . 1 0 1.2 3 2 .0 0 0 .0 3 0 .4 6 0.1 4 0 . 7 5 Ol iv in e ЬО.2 29 .6 100 .0 2 0 . 0 68 23 0 .2 6 0 3 .2 3 1.3 1 0.0 5 0 . 0 9 1.64 Muscovite 7.8 15.1 5 0 .3 4 . 3 30 20 0 . 1 8 3 .1 2 2.00 0 . 1 0 2.33 0.3 3 2 . 9 6 B i o t i t e 2 3 . b 24. b 8 2 . 0 6 .5 2b 14 0 .1 4 4 . 3 7 1. 73 0 . 8 3 0. 8 7 0 .1 4 2 . 0 0 I l l i t e - A 2 . 0 2 .4 7. 7 0 . 2 8 0 . 3 0 .3 8 1.23 2.2 5 0 . 4 5 0. 13 0 .1 7 1 . 2 0 1 1 1 it e - B 25. 3 1 3 .0 43 . 5 4 . 0 38 11 0.1 4 0 1 . 0 0 0 . 9 2 0 0 1. 0 7 111it e-C 1 0. 6 29 .2 9 7 . 0 4 . 3 14 11 0 . 1 1 1.23 2.75 1 . 5 2 0 .6 5 0 . 6 1 2 .9 2 U o nt m o ri ll o n it e- A 1.1 2 0 .0 6 7 .0 0 . 3 23 24 0 .4 1 1.2 3 i i 2. 30 0 . 3 7 0 .0 7 0 .1 3 l . C l M o nt m or il lo ni te -B 1 . 2 24 .1 80. b 0 . 3 2 20 0 . 3 2 D J O 3 . 0 0 1 . 0 0 0 . 4 2 6.15 7.9 5 K a o l i n i t e 1. 8 1 .2 4 . 0 0 . 3 23 10 0 . 1 1 4 . 3 7 2. 2d 0 . 1 3 0.1 0 0 .1 5 0 . 5 2 сл CO T h e sorp ti on of tr a ce e le m e n ts
60 A . K a b a ta -P e n d ia s
Fig. 3. R atios of the reten tio n of trace ele m e n ts (in m.e.) to the CEC of d iffe r e n t m in erals. T he sca le for M n is m u ltip lied by 1 0 - 1
T a b l e 3 R e t e n t i o n and removal o f tr a c e el e m e nt s \ i n m . e , / l Q 0 g) M ineral Co Ni Zn Cu Un Rt Rm Rt Rm at Rm Rt Rm Rt Rm Quartz 4 2 18 4 15 10 2 8 229 91 A l b i t e 9 1 11 4 42 41 35 63 n. d . n. d. O r to c la s e 2 7 7 4 38 23 51 79 220 95 O li v in e 100 68 0 170 57 151 39 175 604 272 Muscovite 51 15 32 6 44 105 47 84 58 379 B i o t i t e 83 22 99 15 84 132 32 75 248 1176 I l l i t e - A 8 1 23 5 15 15 79 70 452 149 I l l i t e - B 44 14 102 19 92 92 54 86 1442 1034 I l l i t e - C 99 15 102 20 89 94 92 108 1б4б 6 9 6 M on tm or il lo ni te -A 68 2 53 14 42 26 91 63 1242 878 ll o n t m o r i l l o n i t e - B 82 2 92 10 92 49 83 59 2378 561 K a o l i n i t e 4 1 37 3 26 8 36 47 211 142 Rt - r e t e n t i o n , Rm - removal
The rem o val of cobalt by o x alate solution ran g es fro m 1 to 68 m.e./100 g (Tab. 3). In general, th e am o u n t rem oved does n ot exceeds 50 p e r cent of th e re ta in e d cobalt (w ith exception of olivine). The stro n gest fix atio n of cobalt occurs in b o th m o n tm o rillonites an d illite -A The
T he sorp tion o f tr a c e elem en ts 61
degree of cobalt so lu b ility as calcu lated on th e basis of its to ta l co n ten t in th e m in e rals (initial co n ten t an d re ta in e d am ount) is m uch m ore u n i fo rm an d varies fro m 10 to 25 p er cent, w ith th e exception of illite-A and q u a rtz (Tab. 2).
N i c k e l . The re te n tio n of nickel by soil-form ing m inerals is v ery sim ilar to th a t of cobalt (Tabs 3 and 4). Q u artz an d feld sp ars accu m u late th e sm allest am o unts of th is elem en t (below 20. m.e./100g). The sorption of n ickel by biotite, illites (В and C) and m o n tm o rillo n ites is of a v e ry sim ilar order. The h ig hest am o u n t of nickel is fix ed by illite-B and С and is h ig h er th a n for o th er elem en ts (Tab. 3). T here is a sm all sorption of n ickel by m uscovite, k ao lin ite and by illite -A w ith a high co n ten t of q u artz.
The cu rve of nickel re te n tio n p lo tted again st th e CEC is sim ilar to those obtain ed fo r cobalt and zinc (Fig. 4). It m ay suggest th a t th e re a c tions involved in th e so rption of th ese cations a re v ery sim ilar, w hich m ay be also due to th e ir ionic rad iu s: Co2+ — 0.83, N i24 — 0.82, Z n 24' — — 0.83 Ä.
Fig. 4. R ela tio n b e tw e e n the r e ten tio n of tra ce elem en ts, cation d isp la cem en t and th e CEC of m in era ls
T here is no d irect rela tio n b etw een nickel re ta in e d and m ajo r cation d isplacem en t (Tab. 4), excep t of some sim ila rity to th e am o un t of M g2 : rem o v al from th e clay m in erals. The ratio of th e re ta in e d nickel to CEC is v e ry o ften h ig h er th a n 1, especially for th e p rim a ry m inerals (Fig. 3).
The rem o v al of nickel b y ox alate solution is calcu lated for all m in e rals, w ith th e ex ception of olivine, over th e ran g e 3 to 20 m.e./100 g (Tab. 3). N ickel is m ore easily e x tra c te d fro m illites and m o n tm orillonites th a n cobalt (Tab. 4).
T a b l e 4 R e te n tio n and removal o f n ic k e l a t 30 ppm a d d itio n
M in e r a l C o n ten t b e f o r e tr e a tm e n t ppm Amount r e t a i n e d ppm P e r c e n t a g e r e t e n t i o n Amount s o l u b l e ppm P e r c e n t a g e re m o v a l C a tio n d i s p la c e d (m g /g ) o f r e t a i n e d amount o f t o t a l c o n t e n t S i 4* A l3+ xlOOO F e ^ xlOO Mg24 r Na+ T o t a l Quartz 1 .4 5 .4 1 8 .0 1 .3 24 19 0 .2 1 0 .6 2 1 .0 0 0 0 .0 5 0 .0 1 0 .2 8 A lb it e 1 .8 3 .2 1 0 .6 1 .2 38 24 0 .1 4 0 .2 0 1 .7 5 0 0 .0 3 0 .2 4 0 .3 3 O r t o c la s e 4 .2 2 .0 6 .7 1 .2 60 19 0 .1 9 0 .6 2 2 .0 0 0 0 .3 9 0 .0 5 0 .6 5 O l iv in e 2 0 8 0 .0 0 0 5 0 .0 - - n . d . n .d . n . d . n . d . n .d . n . d . n . d . M u s c o v ite 4 .7 9 .3 3 1 .0 1 .9 20 14 0 .2 4 3 .1 0 1 .7 5 0 .0 4 2 .2 8 0 .3 3 2 .9 0 B i o t i t e Ю 6.3 2 8 .9 9 6 .0 4 .5 16 3 0 .2 0 2 .5 0 1 .7 5 0 .7 2 0. 80 0 .1 3 1 .9 7 I l l i t e - A 1 .3 6 .7 2 2 .4 1 .4 21 18 0 .2 0 3 .1 2 1 .5 0 0 .3 9 0 .1 6 0 .1 7 0 .9 4 I l l i t e - B 2 5 .0 3 0 .0 1 0 0 .0 5 .7 19 10 0 .1 0 1 .2 5 1 .0 0 1 .0 4 0 0 1 .13 U l i t e - C 3 0 .2 2 9 .9 9 9 .5 6 .0 20 10 0 .1 5 4 .3 7 2 .0 0 1 .5 4 0 .5 8 0 .5 0 2 .7 9 M o n t m o r illo n it e -A 1 1 .2 15.4 5 1 .5 4 .0 27 17 0 .4 9 3 .1 2 1 .7 5 0 .3 4 0 .0 5 0 . 0 8 0 .9 8 M o n t m o r illo n it e - B 3 .5 2 6 .9 9 0 .0 2 .8 11 10 0 .3 3 2 .5 0 1 .0 0 1 .0 8 0 .4 1 5 .9 4 7 .7 7 K a o l i n i t e 2 0 .5 1 0 .8 3 6 .0 1 .0 9 3 0 .1 6 6 .2 5 1 .5 0 0 .0 1 0 .0 5 0 .0 8 0 .3 2 .. K a b a ta -P e n d ia s
T he sorp tion o f tra ce elem en ts 63
Z i n c . The sorption of zinc by illites and m on tm o rillo n ites is sim ilar to th a t of cobalt an d nickel an d ran g es from 42 to 92 m.e./100 g (Tab. 3). Its sorption by q u a rtz and feld sp a rs is h igh and th e ratio of its re te n tio n to th e CEC of th ese m in erals is above 2 (Fig. 3). Q u artz and illlite -Л fix ed only 16 p er cent of zinc added, th is valu e for feld sp ars, m uscovite and m o ntm o rillo n ite-A is abo ut 45 p er cent an d for all o th er m in e rals (apart from olivine) is above 90 p e r cent.
A ccording to J e n n y a nd E l g a b a l y [7] zinc could be sorbed by m o n tm o rillo n ite fro m Z nC l2 solution in th e th re e exchan geab le form s: Z n 2+, Z nO H + and ZnCl+. Besides th e ex ch an geable form s zinc is also fix ed in an u n ex ch an g eab le form . T he e x p e rim e n t of B ingham et al. [1] show s th a t in th e acid C l-sy stem th e sorptio n of zinc w as g e n e ra lly equal to CEC, reg ard less of co n cen tratio n used. B ut in th e solution w ith pH above 5.6 to 6.0 th e p rec ip ita tio n of Zn(O H )2 occured and in creased th e am o u n t of re ta in e d zinc. T h eir evidences an d p a rtic u la ry of B ingham et all m ay be used to ex p lain th e re su lts of th is e x p e rim e n t in term s of th e ab i lity of a soil-form ing m in erals to accu m u late zinc from th e v e ry d ilu te n e u tra l solutions in th e excess of th e ir CEC.
T h ere is not a clear re la tio n sh ip b etw een th e am o u n t of re ta in e d zinc an d m ajo r cation d isplacem ent. O nly d isplaced m agnesiu m as in th e case of nickel, rev eals some ag reem en t w ith th e zinc sorbed by clay m i n e ra ls (Tab. 5).
T he so lu b ility of zinc in th e ox alate solution is v e ry high an d exceeds in m an y cases its re te n tio n (Tab. 5). Zinc in m icas an d illites ex h ib its a rem a rk a b le so lubility , w h ich in d icates th a t so rption by th ese m in erals is based to a high degree on th e exh an g e cation reaction.
C o p p e r . The d a ta for copper re te n tio n an d rem oval are p rese n ted in Tab. 6. P e rce n tag e re te n tio n of copper in th e presence of 0.1 N CaC l2 is q u ite sim ilar to th a t of cobalt, b u t it is m ore u n ifo rm th a n for cobalt. M inerals of th e illite and m o n tm o rillo n ite groups sorbed th e h ig h est am o u n t of copper: from 54 to 92 m.e./100 g (Tab. 3). The sorption of copper by feld sp ars, m icas, k ao lin ite an d also olivine is of th e sam e order. O nly q u a rtz re ta in s a v e ry sm all am o u n t of th is cation (about 2 m.e./100 g). C uC l2-sy stem re te n tio n from d ilu te n e u tra l solution is m uch m ore re la te d to th e CEC of th e m in erals th a n th a t of an y o th er elem en t (Fig. 4). B i n g h a m et al. [1] has show n th a t th e re te n tio n of copper from C l-salts is alm ost eq u al to th e CEC, reg ard less of co n cen tratio n used, b u t fro m v ery acid solutions (pH 2.2 to 2.5). This rela tio n sh ip rev eals th a t an exchange reactio n is involved in th is sorption. In th e pH 6 solution used in th is ex p erim en t, th e re te n tio n of copper in creases th e CEC. The ratio of th e re ta in e d copper to th e CEC is sm aller fo r clay m in erals th a n for p rim a ry
О)
T a b l e 5 R e te n tio n and rem oval o f z in c a t 30 ррш a d d itio n
M in e ra l C ontent b e fo r e t r e a tm e n t ppm Amount r e t a in e d ppm P e r c e n ta g e r e t e n t i o n Amo unt s o l u b l e ppm P e r c e n t a g e re m o v a l C a tio n d i s p l a c e d (m g /g ) o f r e t a i n e d amount o f t o t a l c o n t e n t S i 4* A l^+ xlOOO Fe^+ xlOO Mg2* K* Na+ T o t a l Q uartz 1 5 .0 5 .0 16 .5 3 .2 64 15 0 .1 2 0 .5 0 0 .7 5 0 0 .0 3 0 .0 1 0 .1 7 A l b i t e 31 .3 1 3 .7 4 6 .0 1 3 .5 98 30 0 .0 8 0 .6 2 2 .0 0 0 0 .0 1 0 .1 6 0 .2 8 O r t o c la s e 1 2 .5 12.5 4 2 .0 7 .5 60 30 0 .0 8 1 .8 7 2 .2 5 0 0 .2 8 0 .0 7 0 .4 5 O l iv in e 3 7 .5 18.5 6 2 .0 4 9 .5 89 0 .1 0 2 .5 0 2 .2 5 1 .5 4 o . o i 0 .0 5 1 .7 2 M u s c o v ite 6 5 .5 14.5 4 8 .5 3 4 .5 43 0 .1 8 4 .3 7 2 .2 5 0 . 0 6 2 .3 1 0 .3 3 2 .9 1 B i o t i t e 302 .5 27 .5 9 2 .0 3 7 .0 11 0 .1 7 6 .2 5 2 .0 0 0 .3 0 0 .6 8 0 .1 8 1 .3 5 U l i t e - A 2 0 .0 5 .0 1 6 .5 5 .0 100 20 0 .1 7 3 .7 5 2 .2 5 0 .3 4 0.Ю 0.Ю 0 .7 3 I l l i t e - B 6 0 .0 3 0 .0 1 0 0 .0 3 0 .0 100 33 0 .1 1 1 .2 5 0 .2 5 1 .5 6 0 0 1 .6 9 U l i t e - C 4 6 .3 28 .7 9 5 .5 3 0 .6 40 0 .1 7 6 .2 5 2 .7 5 1 .4 2 0 .5 0 0 .4 0 2 .5 2 M o n t m o r illo n it e -A 2 6.3 1 3 .7 4 5 .0 8 .5 62 21 0 .3 9 3 .1 2 2 .2 5 0 .3 2 0 .0 5 0 .0 9 0 .8 7 M o n t m o r illo n it e -B 1 50.0 3 0 .0 1 0 0 .0 1 6 .0 53 9 0 .3 4 3 .7 0 1 .0 0 1 .0 8 0 .3 7 5 .9 4 7 .7 4 K a o l i n i t e 6 6 .6 8 .4 2 8 .0 2 .5 30 3 0 .1 0 3 .1 2 2 .2 5 0 .1 8 0 .0 3 0 .1 8 0 .5 7 A . K a b a ta -P e n d ia s
R o c z n ik i g le b o z n a w c z e T. a b 1 e 6 R ete n tio n and removal o f copper at 30 ppm a d d itio n
M ineral Content before treatm ent ppm Amount r e ta in e d ppm P ercen tage r e te n tio n Amount so lu b le ppm P ercen tage
rem oval C ation d is p la c e d (m g/g) o f
r e ta in e d amount
o f t o t a l
c o n ten t S i4* A l3+xlOOO Fe5+
xlOO Mg2* K* Na+ T o ta l Quartz 2 .0 0 .5 2 2 .5 - 100 0 .1 7 0 .5 0 0 .5 0 0 .0 2 0 0 0 .2 0 A lb ite 9 .4 1 0 .6 35 2 0 .0 - 100 0 .0 9 0 .6 5 1 .0 0 0 .0 4 0 0 .0 3 0 .1 7 O r to c le se 9 .2 1 6 .3 54 2 5 .0 - 100 0 .0 9 1 .8 5 1 .5 0 0 .0 5 0 .2 5 0 0 .3 1 O liv in e 4 1 5 .0 1 2 .5 42 5 5 .7 - 13 0 .3 7 3 .1 0 1 .5 0 1 .6 1 0 0 2 .0 0 M uscovite 2 3 .8 1 5 .0 50 2 6 .7 - 67 0 .3 0 3 .7 5 2 .0 0 0 .0 2 2 .5 5 0 .1 8 3 .0 7 B io t it e 110.0 1 0 .2 34 2 3 .8 - 20 0 .1 9 3 .1 0 2 .0 0 0 .6 8 1 .1 3 0 .0 3 2 .0 5 I l l i t e - A 1 5 .0 2 5 .0 83 2 2 .0 88 55 0 .1 8 5 .0 0 2 .5 0 0 .4 8 0 .0 5 0 .0 2 0 .6 6 I l l i t e - B 44 .3 1 7 .0 57 2 7 .2 - 45 0 .1 3 4 .5 0 0 .7 5 1 .0 4 0 0 1 .2 5 I l l i t e - C 3 2.5 2 9 . 2 98 3 4 .5 - 57 0 .1 0 6 .2 5 2.0 0 1 .0 8 0 .4 5 0 .4 0 2 .0 5 M o ntm orillonite-A 16.3 2 8 .8 96 2 0 .0 70 47 0 .3 9 3 .1 2 1 .7 5 0 .4 9 0 0 0 .9 0 M o n tm o rillo n ite-B 5 .0 2 6 .2 87 1 8 .7 75 58 0 .3 6 1 0 .0 0 1 .7 5 1 .1 0 0 .3 6 5 .7 9 7 .6 3 K a o lin ite 3 0 .0 11 .3 38 1 5 .2 - 36 0 .1 4 5 . 6 2 2 .0 0 0 .1 9 0 .1 5 0.Ю 0 .6 1 T h e sorp ti on of tr ac e e le m e n ts
66 A. K a b a ta -P e n d ia s
ones (Fig. 3). It m ay suggested th a t th e reactio n s involving th e fo rm atio n of com plex cations (C uO H +, C uC l+) a n d some p recip itatio n of th e m etal (e.g. in form C u/O H /2) p lay im p o rta n t role in th e sorption by p rim a ry m in erals. The a b ility of all soil-form in g m in erals to accu m u late copper from d ilu te n e u tra l solutions in th e presence of 0.1 N CaC l2 is v e ry sig ni fican t for th e p la n t n u tritio n .
No rela tio n sh ip can be observed b etw een copper sorption a n d m ajo r cation d isp lacem ent (Tab. 6), alth o u g h th e cu rve of to ta l cation d isp lace m en t p lo tted ag ainst th e CEC follow s to some e x te n t a sim ilar p a tte rn to th a t for copper re te n tio n (Fig. 4).
The so lu b ility of copper in th e o x alate solution is m uch h ig h er th an th a t of o th er cations an d exceeds th e am o u n t of th e re ta in e d copper, alm ost for all m in erals (Tab. 6). T otal copper (initial an d re ta in e d content) w as soluble fro m q u a rtz an d feld sp ars. A re la tiv e ly less soluble form is th a t of copper fix ed by olivine an d b iotite. The h ig h est so lub ility w as noticed in th e case of m uscovite, illites and m ontm orillonites, w hich cor responds to abo u t 50 p er cent of th e to ta l co n ten t of th is cation.
M a n g a n e s e . T he c o n ten t of m anganese in th e CaCl2 tre a tm e n t sy stem w as eq ual to 1500 ppm . S m aller co ncen tratio n s of M n2+ in solu tion caused th e solubilisatio n of m anganese occuring in u n tre a te d m in e rals. T he in itia l co n ten t of th is cation w as v e ry high, especially in such m in erals as m icas, olivine a n d som e illites (Tab. 7). A ll p rim a ry m in e ra ls (excluding olivine), illite -A an d kao lin ite sorbed a sm all am o un t of m anganese, fro m 58 to 248 m.e./100 g, w hich corresponds to below 10 p er cent of cation added (Tabs 3 an d 7). T he sorption of m anganese by tw o illites an d m on tm o rillo n ites is fro m 1242 to 2378 m.e./100 g, w h at is equal, resp e c tiv e ly to 22 an d 44 p e r cent of th e am ount added. The d a ta o b tain ed for th e m anganese re te n tio n are not com parable w ith those obtain ed fo r o th er tra c e elem ents, n ev erth eless, a sim ilar degree of sorption a b ility of th e m in erals m ay by noticed.
As th e re su lts of H o 1 d r i d g e [6] in d icate, th e c o n cen tratio n of m an ganese in solutions above 50 m.e./100 g k aolinite does not caused any in creasin g of m anganese re te n tio n . This e x p e rim e n t w as conducted at th e m ax im u m so rp tio n a b ility of th e m inerals.
The rep la ce m e n t of m ajo r cations by m anganese show s a g rea t d isp a rity , w hich is less a p p a re n t w ith th e d iv ale n t m agnesium in th e clay m in e rals (Tab. 7). The am o u n t of m anganese re ta in e d p lo tted ag ain st th e
CEC follow s to some e x te n t th e tre n d of such a curve for C u2+ and
d iffers from the curv es o b tain ed for Co2+, N i2+ and Z n 2_f. It m ay in dicate th a t sim ilar reactio n s could be involved in th e sorption of M n2+ and C u24.
T a b l e 7
R e te n tio n and removal of manganese at 150 ppm a d d itio n
M in e r a l C ontent b e f o r e tre a tm e n t ppm Amount r e t a i n e d ppm P e r c e n ta g e r e t e n t i o n Amount s o lu b le ppm P e r c e n t e ç e r e m o v a l C a tio n d i s p l a c e d (m g /g ) o f r e t a i n e d amount o f t o t a l c o n t e n t S i 4* A l * xlOOO Fe^+ xlOO Mg2* K+ Na+ T o t a l Quartz 0 .8 63 4 .2 25 40 39 0 .3 5 0 0 . 7 5 ' 0 .0 2 0 0 0 .4 5 O r t o c la s e 80 60 0 .4 26 - 31 0 .0 9 0 0 .5 0 0 0 .2 9 0 0 .3 9 O l iv in e 800 1166 7 8 .0 749 65 38 0 .4 1 0 1 .0 0 1 .4 0 0 0 1 .8 2 M u sco v ite 270 16 1 .1 104 - 35 0 .1 5 0 1 .0 0 0 .0 5 2.08 0 2 .2 9 B i o t i t e 1950 68 4 .5 323 - 16 0 .1 3 0 0 .7 5 0 .5 3 0 .8 0 0 1 .5 4 I l l i t e - A 30 124 8 .3 41 33 27 0 .1 8 0 1 .2 5 0 .3 9 o . o i 0 0 .5 9 I l l i t e - B 420 396 2 6 .4 284 74 36 0 Д 1 2 .2 5 0 .7 5 1 .1 0 0 0 1 .2 9 I l l i t e - C 320 452 3 1 .0 191 45 58 0 .2 0 2 .5 0 1 .0 0 1 .1 9 0 .4 3 0 .3 1 2 .1 4 U o n t m o r illo n it e - A 195 341 2 2 .8 241 71 45 0 .4 0 1 .2 5 1 .2 5 0 .2 5 0 0 0 .6 6 M o n t m o r illo n it e -B 65 653 4 4 .5 154 23 20 0 .3 4 n . d. 2 .0 0 0 .8 7 0 .2 8 5 .8 3 7 .3 4 K a o l in it e 102 58 3 .8 39 68 25 0 .1 0 1.2 5 1 .2 5 0 .0 5 0 0 0 .1 6 T h e sorp tion of tr a ce e le m e n ts
6 8 A. K a b a ta -P e n d ia s
The am o un t of m ang anese reta in e d , reg ard less of its high concen tra tio n , does not exceed the CEC v e ry m uch for some clay m inerals and for b iotite (Fig. 3). A ll o th er p rim a ry m in erals and tw o illites (B and C) are the exception an d show th a t o th er reactio n s th a n only p u re cation exchange tak e place in th is sorption.
The so lu b ility of m anganese in th e o x alate solution is h ig h er th a n its re te n tio n in b o th m icas an d o rthoclase (Tab. 7). For a ll oth er m in e ra ls it is n o t h ig h er th a n 74 p er cent of th e re ta in e d am ount. M anganese is thu s re la tiv e ly stro n g e r sorbed th a n copper. Since th e sorption of m anganese w as c a rrie d out at h ig h er co n cen tratio n s th a n th e o th er tra c e elem ents it m ay be concluded th a t th e degree of its re te n tio n an d rem o val is sm aller th a n of oth er heav y m eta l cations. The re su lts of th e ex p e rim e n t c a rrie d out by H o 1 d r i d g e [6] clearly confirm e this data.
SU M M A R Y A N D C O N C LU SIO N S
T he e x p e rim e n t conducted on th e fix atio n of tra c e elem ents by p u re p rim a ry and clay m in erals in th e p resen ce of 0.1 N CaC l2 u n d e r sim ilar conditions of pH 6 show s th a t th e am o u nt of h eav y m e ta l cation re ta in e d is alw ays in th e excees of th e CEC (Fig. 3). The ra tio of th e re ta in e d cations to th e CEC is, in general, h ig h er for th e p rim a ry m in erals th a n for th e clay m inerals. It in d icates th a t h ig h er am ou nts of tra c e elem ents are fixed by th e clay m in erals in th e exchan g eab le form s, b u t th e p rim a ry m in erals fix these cations r a th e r b y h y d ro ly sis rea c tio n s occuring on th e ir surfaces. This agrees w ith th e re su lts of B i n g h a m et al. [1] and of H o d g s o n et al. [5].
The g en eralized o rd er of th e a b ility of all m in erals to accu m u late h e av y m etal cations from v e ry d ilu te n e u tra l solution is sum m arized as follows:
Q < Fd < K l < O l < Mt < II
T he k ey to m in eralo g y is given in Tab. 1, w ith th e ex ception of
II, w hich refe rs to all illites an d b o th m icas and of Fd, w hich rep re sen ts
feld sp ars. The above o rd er w as calcu lated on th e basis of p ercen tag e re te n tio n . S im ila r fig u res w ere obtain ed fo r cation re ta in e d in m.e./100 g.
The o rd er of tra c e elem en t fix a tio n in d icates th a t reg ard less of th e im p o rtan ce of h y d ro ly sis reactio n s in th e sorption, th e re is a k in d of rela tio n b etw een th e am o u n t of fix ed tra c e elem ents and th e in te rn a l surface of m in erals. O livine is an exception and its sorp tion is p resu m ab ly to a high degree due to th e chem ical reactio n involved.
T he sorp tion of tr a c e elem en ts 69
The g en eralized ord er of th e rem o v a l of h e av y m eta l cations sorbed b y m in erals in th e o x alate solution is follow ing:
K l c I l c M t c O l c Q < Fd
This o rd er show s a high d isp a rity fro m th a t calcu lated on th e basis of m.e./100 g.
The so lu b ility of th e h e a v y m eta l cations gives an alm ost rev e rsib le o rd er to th a t of th e fix a tio n one. T he less soluble tra c e elem ents w ere those sorbed by feld sp ars, q u a rtz an d olivine. K ao lin ite is one th e clay m in erals releasin g th e sm allest am o u n t of th e re ta in e d tra c e elem ents. This o rd er is v e ry sim ilar to th a t o b tain ed for H C l-soluble cobalt fro m d iffe re n t m in erals b y K a b a t a a nd B e e s o n [9]. T he re su lts of th ese both e x p e rim e n ts show th a t th e sorp tio n of h eav y m eta l cations by k ao lin ite is v e ry sm all an d alm ost u nex ch an g eable.
Som e sim ilarities of th e reactio n s involved in th e sorption w ere e sta blished for tw o groups of th e tra c e elem ents: Co2+, N i2+, Z n 2+, and C u2+, M n2+, basing on th e rela tio n of th e ir re te n tio n to th e CEC (Fig. 4).
The e n try of th e d iv ale n t h e av y m eta l cations into th e p rim a ry m in e ra ls in CaCl2-sy stem m ay be su m m arized as follows:
Co2+ < Cu2+ < Ni2+ < Z n2+
T he sam e o rd er fo r th e clay m in erals d iffers a little and increases as follow s:
Co < Z n 2+ < C u 2+ < N i
2-T hese o rd ers for both groups of m in erals do not d iffe r v e ry m uch w ith an exception of zinc, w h ich is m uch m ore fav o u rab le placed into p rim a ry m in erals th a n clay ones.
T he o rd er of rem o v al of th e trace elem ents b y th e e x tra c tio n w ith o x alate solution is th e sam e fo r both groups, p rim a ry and clay m in erals,
an d increases as follow s:
Co2+ < Ni2+ < Zn2- < Cu2+
This o rd er show s some deviation fro m th e o rd er of th e e n try of div a len t h e a v y m etal cations into th e m in erals, w h a t m ay be possibly e x p la in ed on th e basis of th e ir d iffe re n t solub ilities in th e solution used.
A ll calculatio n fo r th e o rd ers of re te n tio n an d rem o v al of tra c e ele m en ts w ere based on th e am o u nts of m.e./100 g. M anganese w as n o t ta k e n in to consideration because of its d iffe re n t co n cen tratio n in th e tre a tm e n t solutions.
O ne is forced to th e conclusion, th ere fo re , th a t all soil-form in g m in e ra ls of clay-size p a rtic ip a te in th e fix atio n of th ese elem en ts in th e soil. T he m in erals of th e illite an d m o n tm o rillo n ite groups p lay th e m ost im
-70 A. K a b a ta -P e n d ia s
p o rta n t role as concerning th e am o u n t of tra c e elem en t sorbed. B u t m o n t- m o rillonites are m ore sig n ifican t fro m th e sta n d p o in t of p la n t n u tritio n . The tra c e elem en ts sorbed by illites and kao lin ite are less soluble, th u s less available to th e p lan ts, th a n those fix e d by m ontm orillonites.
C obalt seem s to be th e e lem en t m ost stro n g ly fix e d by all m in erals. C opper and zinc are easily exch ang eab le of th e form s sorbed by all m in e rals.
T he a u th o r w ishes to e x te n d h e r th a n k s to Dr. M. K ac-K acas, Dr. M.M. M o rtland , Dr. K. N o rrish , Dr. G. Sem b, Dr. K.G. T iller an d M r. W. Szczepanow ski, M.Sc., w ho collected an d k in d ly sen t th e m in erals used for th is stu d y , a n d also to M r. M. S tępniew ski, M.Sc. fo r X -ra y d iffra c tio n testin g , and to M r. E. B olibrzuch and M r. P. T arłow ski for tec h n ica l assistance.
R EFER EN C ES
[1] B i n g h a m F. T., P a g e A. L., S i m s J. R.: R eten tio n of Cu and Zn by H -m o n tm o rillo n ite. S o il Sei. Soc. A m . Proc., 28, pp. 351— 359, 1964.
[2] В о г с h a r d t G. A., J a c k s o n M. L., H o l e F. D.: E x p a sib le la y e r silic a te g en esis in soils d ep icted in m ica pseu d om orp h s. Proc. Int. C lay C onf. J eru sa lem , 1, pp. 175— 185, 1966.
[3] H о d g s о n J. F.: C obalt rea ctio n s w ith m o n tm o rillo n ite. S o il Sei. Soc. A m . Proc., 24, pp. 165— 168, 1960.
[4] H o d g s o n J. F., T i l l e r K. G.: T h e lo ca tio n of bound on 2 : 1 la y er silica tes. C lay and C lay M inerals. Proc. 9th N at. C onf., pp. 404— 417, 1961. [5] H o d g s o n J. F., T i l l e r K. G., F e l l o w M.: T he role of h y d ro ly sis of
h ea v y m eta ls w ith so il-fo r m in g m a teria ls. S o il Sei. Soc. A m . Proc., 28, pp. 42— 46, 1964.
[6] H о 1 d r i d g e D. A.: T he sorp tion of h e a v y m eta l cation s by b a ll clay. Proc. Int. C lay Conf. J eru sa lem , 1, pp. 341— 349, 1966.
[7] J e n n y H., E l g a b a l y M. M.: C ation and anion in terch a n g e w ith zinc m o n tm o rillo n ite clays. J. P h y s. Chem ., 47, pp. 399— 405, 1943.
[8] K a b a t a A.: P rzegląd fo to m etry czn y ch m etod ozn aczan ia m ik ro elem en tó w w ro ślin a ch i w gleb ach . P a m ię tn ik P u ła w sk i, 3, pp. 81— 91, 1961.
[9] K a b a t a A. , B e e s o n K. C.: C obalt u p ta k e b y p la n ts from cob alt im p reg n ated so il m in era ls. S o il Sei. Soc. A m . Proc., 25, pp. 125— 128, 1961.
[10] K a b a t a - P e n d i a s A.: B ad an ia g'eoch em iczn o-m in eralogiczn e g leb w y tw o rzonych z g ra n itó w i b a za ltó w D oln ego Ś ląsk a. R oczn. N au k R oln., 9 0 -A -l, pp. 1— 60, 1965.
[11] K a b a t a - P e n d i a s A.: B ad an ia g e o ch em iczn o -m in era lo g iczn e d w óch gleb w y tw o rzo n y ch z p ia sk o w có w . R oczn. N auk R oln., 92-A -2, pp. 185— 213, 1966. [12] M a c k e n z i e R. C.: A m icrom eth od for d eterm in a tio n of c a tio n e x c h a n g e
cap acity of clay. J. C olloid Sei., 6, pp. 219— 222, 1951.
[13] M e h l i c h A., C o l e m a n N. T.: T yp e of so il colloid and m in era l n u trition of p lan ts. A dv. in A gr., 4, pp. 67— 99, 1952.
£14] T i l l e r K. G., H o d g s o n J. F., P e e c h M.: S p ecific sorption of cob alt by so il clays. S o il Sei., 95, pp. 392— 399, 1963.
T h e sorp tion of trace e lem en ts 71
A . K A B A T A - P E N D I A S
L ’A B SO R P T IO N D ES O L IG O -ÉL É M E N T S P A R LES M IN É R A U X D ES SO LS
S e c t i o n d e s O l i g o - é l é m e n t s d ’i n s t i t u t l ’A g r i c u l t u r e et. d e P é d o l o g i e à P u ł a w y R é s u m é
A u cours de l ’e x a m en de l ’ab sorp tion des cation s des m éta u x lou rd s (Со, N i, Zn, Cu, Mn) par le s m in éra u x d étritiq u es et a r g ile u x on a pu co n sta ter qu e la q u a n tité des cation s absorbés d ép asse la cap acité d’éch a n g e de ces m in éra u x . L ’ab sorp tion des o lig o -é lé m e n ts depend au ssi b ien des réaction s d’éch a n g e des ca tio n s q u e de réa ctio n s ch im iq u es dont le r ésu lta t est la form a tio n des co m b in a iso n s co m p lex es sur la su r fa c e des m in éra u x . On a c la s s ifie le s m in éra u x et les o lig o -é lé m e n ts e x a m in é s selo n leu r ca p a sité pour l ’absorption.
A . K A B A T A - P E N D I A S
D IE SO R PTIO N DER SPU R E N E L EM E N TE D U R C H DIE B O D EN M IN E R A L IEN
S p u r e n e l e m e n t e l a b o r a t o r i u m d e s I n s t i t u t s f ü r A c k e r b a u , D ü n g u n g u n d B o d e n k u n d e i n P u ł a w y
Z u s a m m e n f a s s u n g
D ie d u rch g efü h rten E x p e r im e n te m it der S orp tion der K ation en v o n S c h w e r m e ta lle n (Co, N i, Zn, Cu, Mn) durch d ie sek u n d ä ren d etritisch en und to n ig en M in era le h ab en gezeig t, d ass die Z ah l der g eb u n d en en K a tio n en höher w ar als d ie K a tio n en a u sta u sch k a p a zitä t d ieser M in erale. D ie S orp tion der S p u ren elem en te fan d n ich t n u r in F o lg e des K a tio n a u sta u sch es sta ff, son d ern au ch in F o lg e der c h e m i sch en R ea k tio n en , d ie zur E n tsteh u n g v o n K o m p lex v erb in d u n g en au f der O ber flä c h e der M in era le fü h rten . Es w u rd en d ie S o rp tio n reih en fü r die ein zeln en M i n e r a le und fü r d ie S p u ren elem en te b estim m t.
A . K A B A T A - P E N D I A S
SO R PC JA PIE R W IA ST K Ó W ŚL A D O W Y C H PRZEZ M IN E R A ŁY GLEBOW E
L a b o r a t o r i u m M i k r o e l e m e n t ó w , I n s t y t u t u U p r a w y , N a w o ż e n i a i G l e b o z n a w s t w a , P u ł a w y
S t r e s z c z e n i e
P rzep row ad zon o bad an ia sorp cji i d esorp cji p ie r w ia stk ó w śla d o w y ch (Co, Ni, Zn, Cu, Mn) p rzez d etry ty czn e i ila ste m in era ły , w y stę p u ją c e p o w szech n ie w glebach. Ilość w ią za n y ch k a tio n ó w m e ta li ciężk ich p rzew y ższa ła w y m ie n n ą p ojem n ość so rp
72 A. K a b a ta -P en d ia s
cy jn ą ty ch m in era łó w . S orp cja p ie r w ia stk ó w śla d o w y c h zachodziła n ie ty lk o w w y n ik u rea k cji w y m ia n y k a tio n ó w , a le i rea k cji ch em iczn ych , p row ad zących do p o w sta n ia k o m p lek so w y ch zw ią zk ó w na p o w ierzch n i m in era łó w .
U sta lo n o szereg so rb ow an ia d w u w a rto ścio w y ch k a tio n ó w m e ta li ciężk ich przez p oszczeg ó ln e m in e r a ły oraz szereg i w e jśc ia ty c h k a tio n ó w do k o m p lek su sorb - cyjn ego. А . К А Б А Т А - П Э Н Д И А С С О РБЦ И Я М И КРО ЭЛ ЕМ ЕН ТО В ПО ЧВЕН Н Ы М И М И Н ЕРА Л А М И Л а б о р а т о р и я М и к р о э л е м е н т о в И н с т и т у т а А г р о т е х н и к и , У д о б р е н и я и П о ч в о в е д е н и я в П у л а в а х Р е з ю м е П роводились и ссл едован и я по сорбции м икроэлем ентов (Со, N i, Zn, Cu, Mn) клястическим и и глинисты ми минералам и вы ступаю щ им и обы кновенно в почвах. О бн ар уж ен о, что количество сор бированны х м икроэлем ентов перев ы ш ает в ел и чи н у емкости поглощ ения эти х м инералов. С орбция д в у х в а л ен т н ы х элем ентов п р ои сход и л а н е только путем реак ц и и обм ена катионов, но т а к ж е в сл едств и е х и м и ч еск и х реакци и, в ед у щ и х к образованию к ом п лек сн ы х соеди н ен и й на п ов ер хн ости м инералов. У становлен ы ряды нек оторы х м инералов по и х сп о собности к сорбированию м икроэлем ентов, а т а к ж е ряды д в у х в а л ен т н ы х м и - к роелем ентов по и х количеству, в котором они сорбирую тся м инералам и.
