TOPRAKLARIN ANAEROBiK KOŞULLARDAKİ REDOKS POTANSİYELİ ÜZERİNE BİR ARAŞTIRMA

Abstract

OZET Bu calr.sma anaerobik kosullarda kum kulturune ilave edilen organik madde, NO], Mn02 ve FeiO J gibi bilesiklerin sistemin redoks potansiyeline etki durumunu iie ayflra bazi orneklerin pH degeri, Fe++, Mn-;-'~ konsatrasyonlanna gore hesaplanan ve olculen redaks potansiyeliller; arasindaki iliskileri arastirmak amaci ile yapilmistir. Lahoratouvarda yurutule~ bu calismada, deneme basinda ve 35 gun sonra dokuz ornekte pH ve Eh degerlerl olculmustur. Deneme sonunda ayrica topo i raklarda ve Fe203 ilave edilmis ornekte fe++, mangan dioksit ilave edilmis ornekte ise Mn+ 1- tayinleri yapilmistir. Deneme ~asmda 4.18 ile 7.00 arasinda degisen pH degerleri arasinda deneme sonunda (5 orryekte azalma, 4 ornekte artis) 5.05 ile (i.58 arasinda, deneme basinda 0.265 yoli ile O~470 volt arasinda degisen redaks potansiyeNeri (tum orneklerde azalma) ise deneme Sonunda 0.020 Volt ile 0.400 Volt ara smda bulunmus/ur. Kum + su, kum -+ .~u + kuru ot, kum + KNO 3 kuru or, .kum -:- su MnO 2 +kuru ot ve kum + su + JieiO 3 + kuru ot ilave edilen 5farkli kum kulturunde deneme sonunda olculen Eh deterleri sirasiyla 0.400, 0.260, 0.220, 0.180 ve 0,175 Volt olarak tesbit edilmistir. Elde edileii bu degerler literaiiirde bu konuda. verilen sinirlarin icerisindedir. SUMMARY A STUDY ON REDOX POTENTlAL OF THE SOIL SAMPLES UNDER ANAEROBIC CONDITIONS lihe objective of this study was· to determine the effects of the additions of dried grass, KNO3, MnO2' and Fe 20 3 on the oxidation-reduction patentiols of the sand culture kept under submerged eonditions for 35 days. Four soil samples 120 were also included in the study. Eh and pH values ot' the five sand eultures and fOUf soil samples were determined in the begiiiing, and at the eiid of the 35 days of submergence. In addition to the determination of FeF contents of the soil samples, Fe++ and Mn-! + analysis were also made on the sand cutures which ,received Fe203 and Mn02' In the begining of the experiment pH and Eh values of the nine samples varied from 4.18 ,to 7.00 and, from 0.265 to 0.470 Volts resp~ctively. At the end of the experiment pH values was found between 4.05 and 6.58, while five samples \. showed slight decreases and fOUf samples showed Increases. All of the samples, showed decreases in Eh values, and at the end of experiment they changed from 0.20 to 0.500 Volts. Sand -I-water, Sand-water, sand+water-dried grass, sand·!... KN03 solution + dried grass, sand +- water -1 Nn02 -i- dried grass, and sand +water + Fe 20 3 -:-- dried grass samples h<!d Eh vel~es, as 0.500, 0.260, 0.200 0.180 and 0.175 volts, 'respcctiveHy. The observed Ehvalue was much lower than the calculated Eh value, developed for pure Mn02+ Mn-+ systems. In some of the samples observed 'redox potentials determined with platinum electrode were 'found to be different than the Eh values cakulated according to. equations developed for the pure iron (III) and irom. (Il) hydroxictessystems.