DESTRUCTION OF CHLORINE-CONTAINING ORGANIC AGENTS IN A 
SYSTEM PLASMA – LIQUID
V.Ya. Chernyak 1, V.V. Yukhymenko 1,  I.L. Babich 1, V.A. Zrazhevskyy 1, Ya.B. Tarasova 2, 
Y.I. Slyusarenko1, Yu.V. Woewoda 1, Yu.A. Chaban 1, A.K. Trokhymchuk 1
1 Radiophysical and Chemical Departments, Taras Shevchenko Kyiv National University,  
Volodymyrska st. 64, Kiev 01033, Ukraine, e-mail: chern@univ.kiev.ua;
2 Institute of Biocolloidal Chemistry of Ukrainian National Academy of Science,
Prospect Vernadskogo St. 42, Kyiv, 03142, Ukraine
The plasmachemical destruction of persistent toxic agent 1,1-di(4-chlorophenol)-2,2,2-threechlorethane (DDT) in 
water solutions is researched in this work. The destruction of agricultural pesticide containing DDT was carried out in 
water solution at atmospheric pressure with usage of plasma treatment on the basis of secondary discharges with a 
"liquid" electrode, and of combination of a plasma method with reagent method. The comparative analysis of results of 
the physical-chemical analysis and biological test of toxicity of solutions is carried out and  the optimum regimes for 
destruction and detoxication of DDT in water are determined.
PACS:52.80.-s,Mg,Wq;52.77Bn,Fv
1. INTRODUCTION
At  present  the  huge  amount  of  anthropogenous 
contaminants  are  accumulated  in  the  world.  The  most 
dangerous  contaminants  on  international  standards  are 
dioxins, polychlorbiphenyls and pesticides [1]. The basic 
migration  of  these  contaminants  to  bio  objects  occurs 
through  waste  and  ground waters.  Therefore  the  major 
attention is given now to development of new advanced 
oxidative  technologies  (AOT)  of  water  purification  to 
which the different plasma technologies belong. 
The usually plasma technologies of water purification 
create on the basis of self-maintained electric discharges 
which  ones  generate  non-equilibrium  plasma:  corona 
discharge, barrier discharge,  combination of corona and 
barrier discharge, diaphragm discharg, gliding arc.
The numerous investigations of plasma treatment of 
water  with  an  organic  pollutants  have  shown  effective 
degradation  of  an  initial  pollutant.  However  physical-
chemical  analysis  has  shown  an  appearance  of  high-
molecular substances in water after plasma treatment.
Interest to investigation of toxicity of output products 
of  plasma  chemical  processes  also  is  bound   with 
necessity of the solution of a problem of feed-backs for 
ecological   plasmachemical technologies such as  water 
purification   and destruction of a toxic waste. The real 
opportunities  (physical  and  economical)  of  modern 
methods  of  the  physical-chemical  analysis  of  multi-
component  solutions  of  high-molecular  compounds  do 
not allow to hope for their usage for a primary signal of 
feed-backs. But today some biological tests of toxicity are 
rapid and cheap  [2].
2. METHODS
The  choice  of  the  schema  of  plasmachemical 
treatment of water was bound with necessity of realisation 
of the following requirements:
• Operation at atmospheric pressure;
• Big contact area of plasma with liquid;
• Permanency  and  uniformity  of  plasma  parameters 
near an interaction range of plasma with liquid;
• Flexibility  of  control  of  plasma  chemical  action  on 
liquid.
The  first  requirement  ensures  a  simplicity  and  low 
cost price of technology. The second requirement ensures 
a  high  productivity  of  treatment.  The  third  and  fourth 
requirements should ensure minimisation of spectrum of 
waste products. The confrontation of these requirements 
and physical properties of such classic electric discharges 
as  barrier,  corona  and  spark  show  their  feeble 
compatibility. As the plasma of these discharges is non-
stationary or heterogeneous.
Besides the peculiarity of this gas-discharged systems 
on  the  basis  of  self-maintained  discharges  is  a  relative 
coherence  between  various  plasma  parameters. 
Independent  control  by  energy,  concentration  and 
composition  of  charged  particles  is  impossible  in  an 
interaction range of plasma with the liquid, as practically 
one external factor (electric field) determines an existence 
of plasma.
Therefore treatment of water with pesticide containing 
DDT was conducted in plasmachemical reactors on the 
basis  of  secondary  discharge  with  a  "liquid"  electrode. 
The key peculiarity of  such secondary discharges  is  an 
independent  control  of  plasma  parameters  in  an 
interaction range "plasma - liquid" and stream of charged 
particles through an interaction range.
The flowing plasma chemical reactor for treatment of 
solution  (Fig. 1) consisted from the glass cylinder (1), a 
diameter of 120 cm, which was closed by the cover (3). A 
free jet of atmospheric air ran from the nozzle (4) across 
two opposite electrodes (5) and formed a bright crescent-
shaped electric arc. We used the rod  graphite electrodes 
with  diameter  d =  5  mm.  A nominal  gap  between the 
electrodes from which we started usually was δ = 1 mm. 
The air nozzle (4) was axisymmetric, with inner diameter 
∅ = 1 mm, made from stainless steel. It was maintained 
vertically in a plain of the electrodes (5) at the length L = 
5 mm and was centered strictly between the electrodes. 
The  exhaust   gases came out  of  a  reactor  through two 
holes  (6)  with  diameter  6  mm  in  the  cover  (3).  The 
current of secondary discharge rans through a plasma (7) 
of arc discharge, a transition layer (8) and a liquid. The 
172                      Problems of Atomic Science and Technology. 2005. № 1. Series: Plasma Physics (10). P. 172-174
distance between electrodes of arc discharge (5) and an 
electrode of secondary discharge (2) was h1 = 1 cm.
The  power  supply  (Pd)  of  the  secondary  discharge 
connected to one of electrodes of arc discharge (5) and to 
an electrode (2).  The source of alternating current   (50 
Hz) or of DC was a power supply (Ps) of arc discharge. 
The secondary discharge is  powered by the DC source. 
The secondary discharge was with the "liquid" cathode or 
with  the  "liquid"  anode  depending  on  polarity  of  the 
electrode (2).
Distinctive peculiarity of the flowing plasma chemical 
reactor was a continuous input of the solution by the axial 
channel,  a  diameter  of  1.5  mm,  of  duralumin  conic 
electrode of the secondary discharge (2), a diameter of 1.5 
mm  and  a  taper  angle  of  60°.  The  electrode  (2)  was 
submerged in a plasma of the arc discharge. 
The  stream of  air  was  80  cm3/s  in  all  investigated 
regimes.  Exhaust  gas  bubbled through a column of  the 
satiated  solution  of  alkali  (NaOH),  a  height  of  5  cm, 
before emission in an atmosphere.
The  toxic  agent  1,1-di(4-chlorophenol)-2,2,2-
threechloroethane ((C6H4Cl)2CHCCl3) (DDT) in form  as 
agricultural chlorine-containing pesticide (superfine clay / 
non-ionic surfactant /  DDT: 0.65/0.05/0.3) were used as 
objects  of  research.  Technical  agricultural  pesticide 
contains  30%  DDT  at  weight.  It  dissolves  in  a  water 
because  of  presence  of  the  surfactants.  The  water 
emulsion  with  a  pesticide  had  a  DDT  concentration 
1kg/m3.
 UV absorption spectroscopy method was applied for 
analysis  of  the  destruction  of  DDT in  water  emulsion. 
The light source used in this analysis is a deuterium lamp. 
The  dependence  of  an  absorption  coefficient  of 
solutions at  λ = 270 nm was applied for  a  quantitative 
assessment  of  concentration  of  pesticide  in  a  solution 
after  plasma  treatment.  The  strong  absorption  of  water 
after plasma treatment was watched in the area of wave 
lengths  smaller  250  nm  because  of  occurrence  of 
hydrogen  dioxide  in  it.  The  standard  ion-metrical 
procedure was used for a measurement of pH of solutions.
The  toxicity of  solutions  was  determined  on  their 
influence on habitability of biological objects. As objects 
the  microorganisms  Daphnia  magna were  used,  as  the 
study  of  habitability  such  organisms  underlies  the 
standard biological tests on the toxicity [3].
This  bio-test  of  the  toxicity  are based  on  the 
measurements of the life time of such organisms in tested 
solutions.  Distilled  water  at  room  temperature  was  a 
control solution at examination of solutions on toxicity.
3. RESULTS AND DISCUSSIONS
The  typical  absorption  spectrums  of  solutions  after 
plasma treatment with the  "liquid" cathode and anode are 
shown in Fig. 2 for currents  of auxiliary discharge Is = 
400 mA and secondary discharge Id = +200 mA (curve 2) 
and -200 mA (3), initial solution (curve 1). 
As it is visible from  Fig.2 destruction has  place. The 
output products are chemical steady in time, about which 
testify spectra of absorption shown on Fig. 3 (curve 1 - 
initial solution of  pesticide; 2 - after treatment; 3 - in day 
after  treatment). However  it  is  impossible  to  identify 
output products on spectra of absorption.
The  essential  question  is  the  toxicity  of  output 
products.  It  was  checked  up  with  measurement  of  life 
time of population Daphnia magna and has shown, that it 
has decreased in 2.5 times in comparison with an initial 
solution (Fig. 4). 
It  was  shown  earlier  [4],  after  plasma  treatment  of 
distilled  water  the  oxidizing  agents,  such  as  hydrogen 
peroxide  and  oxides  of  nitrogen  (H2O2,  HNO2,  HNO3) 
were  formed.  This  fact  well  illustrates  by  absorption 
spectra of  water after plasma treatment (Fig. 5).  Possibly
173
Fig.1. Experimental system for water treatment   in
flowing  regimes
WV
7
8
1
5
2
Gas 3
h1
+(-)
+(-)
-(+)
-(+)
Is
Id
Rb
Pd
Ps
Liquid
4
Gas6 6
0
0,5
1
1,5
2
200 250 300 350 400λ , nm
k, cm-1 1
2
3
Fig.2. Absorption spectrums of water solution 
of  DDT pesticide
0,5
1
1,5
2
200 250 300 350 400λ , nm
k, cm-1 1
2
3
Fig.3. Dependence of absorption spectrums of 
water solution of DDT pesticide from time
the presence of these oxidizers decreased the life time of 
population  Daphnia  magna (Fig.  4).  More  that  and 
standard ion-metrical procedure has shown a decreasing 
of pH from pH = 6.8 in an initial solution of pesticide to 
pH = 3.35 in  these solutions  after  plasma treatment.  It 
indicates  on  appearance  of  acid  properties  of  treated 
solutions. Therefore was logical to add in the treatment 
solutions alkali for neutralization of oxidizers. Results of 
such researches on Fig. 4. From these results it is visible, 
that  by  adding of  alkali  the  toxicity  of  solutions  is 
decreased.
4. CONCLUSION
The  present  study  reveals  that  the  destruction  of 
persistent toxic agricultural pesticide containing DDT  in 
plasma-liquid  system  of  secondary  discharges  with  a 
"liquid" electrode is a reliable and effective process.
The  plasmachemical  treatment  on  the  basis  of 
secondary discharge with a “liquid” electrode can provide 
effective  destruction  of  chlorine-containing  pesticide  in 
water. However growth of destruction of DDT is tracked 
by  growth  of  toxicity  of  solutions  from appearance  of 
oxidizing agents in water after plasma treatment  (H2O2, 
HNO2, HNO3).
The  usage  of  complex  plasma  +  reagent  (NaOH) 
treatment can guarantee not only pesticide destruction in 
water, but also the small toxicity of output products.
5. REFERENCES
1. V. M. Shestopalov, O. G. Molozhanova. Prediction 
of pesticides behavior in subsurface water//  Fate of  
Pesticide Behaviour in Subsurface Water ed. by J.L. 
Schnoor. N.Y., 1992, pp. 371-384. 
2. W.H.  Schalie,  T.R.  Shedd,  et.al.  Using  higher 
organisms  in  biological  early  warning  systems  for 
real-time  toxicity  detection// Biosensors  & 
Bioelectronics, 2001, vol. 16, pp. 457-65. 
3. Citizen’s Guide to Pest Control and Pesticide Safety. 
EPA 730-K-95-001, pp. 11-12.
4. V.Ya.  Chernyak,  V.A.  Zrazhevskyy,  et.al.  The 
peculiarity  of  water  conduct  in  plasmachemical 
reactor  with  “liquid”  electrode//  Bulletin  of  the 
University of Kiev. Series: Physics & Mathematics,  
2003, №1, pp. 307-315, (in Ukraine).
УНИЧТОЖЕНИЕ ХЛОР–СОДЕРЖАЩИХ ОРГАНИЧЕСКИХ ВЕЩЕСТВ В 
СИСТЕМЕ ПЛАЗМА-ЖИДКОСТЬ
В.Я.Черняк, В.В.Юхименко, И.Л.Бабич, В.А.Зражевский, Я.Б.Тарасова, Ю.И.Слюсаренко, Ю.В.Воевода, 
Ю.А.Чабан, А.К.Трохимчук
В  работе  исследовалась  плазмохимическая  деструкция  устойчивого  токсичного  вещества  1,1-ди(4-
хлорфенол)-2,2,2-трихлорэтан  (ДДТ)  в  водных  растворах.  Деструкция  сельскохозяйственного  пестицида 
содержащего  ДДТ  проводилась  в  водном  растворе  при  атмосферном  давлении  с  использованием  как 
плазменной методики на основе вторичных разрядов с «жидким» электродом, так и комбинации плазменного 
метода с реагентным методом. Проведен сравнительный анализ результатов физико-химического анализа и 
биологического  контроля  токсичности  растворов  и  на  его  основе  определены   оптимальные  режимы  для 
деструкции и детоксикации ДДТ в воде.
ЗНЕШКОДЖЕННЯ ОРГАНИЧНИХ РЕЧОВИН, ЩО МІСТЯТЬ ХЛОР, У СИСТЕМІ 
ПЛАЗМА-РІДИНА
В.Я.Черняк, В.В.Юхименко, І.Л.Бабіч, В.А.Зражевський, Я.Б.Тарасова, Ю.І.Слюсаренко, Ю.В.Воевода, 
Ю.О.Чабан, А.К.Трохимчук
В  роботі досліджувалась плазмохімічна деструкція стійкої  токсичної  речовини 1,1-ді(4-хлорфенол)-2,2,2-
трихлоретан  (ДДТ)  у  водних  розчинах.  Деструкція  сільскогосподарського  пестициду,  що  містить  ДДТ, 
проводилась  у  водному  розчині  при  атмосферному  тиску  з  використанням як  плазмової  методики на  базі 
вторинних  розрядів  з  «рідим»  електродом,  так  і  комбінації  плазмового  методу  з  реагентним  методом. 
Проведено порівняльний аналіз результатів фізико-хімічного аналізу та біологічного контролю за токсичністю 
розчинів та на його базі визначені оптимальні режими для деструкції та детоксикації ДДТ у воді.
174
0
20
40
60
80
100
0 100 200 300 400 500
Td, min
Nd, % DDT initialDDT"+"
DDT"-"
Distilat
Distilat"+"
Distilat"-"
Distilat"+"(+NaOH)
Distilat"-"(+NaOH)
DDT"+"(+NaOH)
Fig.4. Dependence of life time of Daphnia 
magna population
-0,05
0
0,05
0,1
0,15
225 275 325 375
λ, nm
k, cm-1 "A+""A-"
Fig.5. Absorption spectrums of distilled 
water after plasma treatment