Natural abiotic formation of oxalic acid in soils: results from aromatic model compounds and soil samples.
نویسندگان
چکیده
Oxalic acid is the smallest dicarboxylic acid and plays an important role in soil processes (e.g., mineral weathering and metal detoxification in plants). We have first proven its abiotic formation in soils and investigated natural abiotic degradation processes based on the oxidation of soil organic matter, enhanced by Fe(3+) and H(2)O(2) as hydroxyl radical suppliers. Experiments with the model compound catechol and further hydroxylated benzenes were performed to examine a common degradation pathway and to presume a general formation mechanism of oxalic acid. Two soil samples were tested for the release of oxalic acid and the potential effects of various soil parameters on oxalic acid formation. Additionally, the soil samples were treated with different soil sterilization methods to prove the oxalic acid formation under abiotic soil conditions. Different series of model experiments were conducted to determine a range of factors including Fe(3+), H(2)O(2), reaction time, pH, and chloride concentration on oxalic acid formation. Under certain conditions, catechol is degraded up to 65.6% to oxalic acid referring to carbon. In serial experiments with two soil samples, oxalic acid was produced, and the obtained results are suggestive of an abiotic degradation process. In conclusion, Fenton-like conditions with low Fe(3+) concentrations and an excess of H(2)O(2) as well as acidic conditions were required for an optimal oxalic acid formation. The presence of chloride reduced oxalic acid formation.
منابع مشابه
Carbon suboxide, a highly reactive intermediate from the abiotic degradation of aromatic compounds in soil.
The formation of volatile compounds during abiotic degradation processes of aromatic compounds in soil has been the subject of many experimental studies but should be examined further. In this context, the present work investigates the natural formation of carbon suboxide using the model compounds catechol and 3,5-dichlorocatechol and also a soil sample from a peat bog. The measurements were pe...
متن کاملمقایسه اسیدهای آلی با وزن مولکولی کم در توصیف آزاد شدن روی در تعدادی از خاکهای آلوده
The rate of metal transfer from the solid phase to solution is an important factor governing their concentration in the soil solution and its availability. In this research, the release rate of Zn in contaminated soils from Isfahan was studied using solutions citric acid, oxalic acid and malic acid 0/01 M during the period of 2 - 504 hours and its relationship with soil characteristics was inve...
متن کاملتأثیر اسیدهای سیتریک و اگزالیک بر ویژگیهای جذب فسفر در برخی خاکهای آهکی
Organic acids can affect phosphorus (P) sorption. In order to evaluate the effect of citric acid and oxalic acid on phosphorus sorption characteristics in calcareous soils, five different soil samples (0-30 cm) were collected in West Azerbaijan province. Soil samples (2.5 g) were equilibrated with solutions of KH2PO4 containing 0 to 20 mg P l-1. Five mM organic acids were added to each tube and...
متن کاملسینتیک آزادسازی پتاسیم غیرتبادلی در افقهای سطحی و زیرسطحی سریهای غالب خاکهای استان کهگیلویه و بویراحمد
The aim of this study was to assess the kinetics of nonexcheangable potassium release in surface and subsurface soil horizons, using organic and inorganic extractions, in Kohgilouye-va-Boyerahmad Province. Kinetics of K+ release was studied by successive extractions of K from 64 selective surface and subsurface soil samples, using 0.01 M CaCl2 and 0.01 M oxalic acid, for 1948 h, with two replic...
متن کاملEcological Risk Assessment and Source identification of PAHs by PMF model in petroleum contaminated soils; West of Kermanshah province
We collected soil samples at 23 sites from the petroleum contaminated soils (PC) in the west of Kermanshah province to investigate the sources and ecological risk of polycyclic aromatic hydrocarbons (PAHs). In this study, source apportionment has been carried out using Positive Matrix Factorization (PMF).The total PAHs concentration, have a mean value of 92.79 mg/kg, ranging from 7.37 to 609.67...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- Environmental science & technology
دوره 47 3 شماره
صفحات -
تاریخ انتشار 2013