Effects of Different Ions on Mobility of Paraquat in Films of Soil Clays

不同離子對巴拉刈在土壤粘粒膜層中移動性的影響

陳鴻基(Horng-Ji Chen)

《農林學報》 49卷4期 (2000/12) Pp. 1-17

https://doi.org/10.30089/JAF.200012.0001

摘要

巴拉刈是台灣廣被使用的一種殺草劑，可強有力地吸附在土壤中，不過其移動性會受到不同粘土礦物種類之層面電荷所影響。其對地下水潛在的污染性是值得注意和關切。因此，採用電化學循環式伏安法技術進一步探討其在天然土壤粘粒中的移動性。試驗結果指出巴拉刈的陰極還原電流會隨著其在粘粒膜層中移動速率之增加而增加。Fe(上標 2+)的存在會影響巴拉刈陰極還原電流的量，其主要乃因電極表面上的Fe(上標 2+)會接收電子造成巴拉刈陰極還原電流量減少，另外由於粘土礦物O平面上已被還原之Fe將巴拉刈二價離子還原成一價離子，使偵測到的還原電流量減少。此外，Fe(上標 2+)的存在會影響巴拉刈的還原電流暈、移動性和可逆性，其也受到SO4(上標 2-)在土壤粘粒邊緣的特殊性吸附與SO4(上標 2-)和粘土礦物O平面上內閣複合物之Fe(上標 2+)的鍵結所影響。這些平面上的特殊負電荷會影響巴拉刈的陰極還原電流量與可逆性。電化學循環式伏安法技術是一種可用來探討研究巴拉刈在粘土礦物與土壤粘粒表面上吸附機制的方法和工具。

關鍵字

層面電荷 ； 巴拉刈 ； 循環式伏安法

並列摘要

Parraquat is a herbicide which have been widely used in Taiwan. It can be adsorbed strongly by soils, but its mobility may be affected by layer charge of different clay minerals. Its potential pollution for ground water will be attended and concerned Therefore， we studied the mobi1ity of paraquat in natural soil clays with cyclic voltammetry technique of electrochemistry. The results indicated that peak currents of cathods (i(subscript pc)) of paraquat (PQ(superscript 2+)) increased with the increase of mobility， and Fe(superscript 2+) affected the amounts of i(subscript pc) that had re1ation with receiving electron of Fe(superscript 2+) from electrode's surface causing decrease of i(subscript pc). Moreover, reduced Fe of inner-sphere complex on O plane promoted reduction of PQ(superscript 2+) to (PQ(superscript +). Furthermore, presence of Fe(superscript 2+) would affect i(subscript pc) mobility and reversibility of PQ(superscript 2+), that were mainly affected by special adsorption of SO4(superscript 2-) on edges of soil clays and bonding between SO4(superscript 2-) and Fe(superscript 2+) of inner-sphere complex on O plane of c1ay minerals. Special negative charge of those planes could affect i(subscript pc) and reversibi1ity Of PQ(superscript 2+). Cyclic voltammetry technique of electrochemistry was a method and tool used to study adsorptive mechanisms of paraquat ions on c1ay minerals and soil clays.

並列關鍵字

Layer charge ； Paraquat ； Cyclic voltammetry