tannins and benzotriazole

To clarify the role of dissolved organic matter (DOM) in sorption of organic pollutants, batch experiments on effects of two representatives of DOM (dissolved humic acid (HA) and tannic acid (TA)) on sorption of benzotriazole (BTA) to a sandy loam soil were conducted. Both HA and TA promoted BTA sorption to soil. Strong positive correlation between sorbed amount of BTA and DOM confirmed the contribution of cumulative sorption by HA or TA in enhancing BTA binding. TA promoted BTA sorption more obviously than HA by providing more sites. For HA with complex structure composed of heterogeneous fractions, its high molecular weight (>3200 Da) fraction could be preferentially sorbed by soil, and it can enhance BTA sorption more obviously than the low molecular weight fraction. The promoting effect of HA on BTA sorption decreased with pH increasing from 6.5 to 10.5 due to reduced sites and electrostatic repulsion between anionic BTA, HA and soil. Sorption of neutral BTA to soil affected by DOM could be well predicted by a modified Freundlich model with K

Topics: Adsorption; Humic Substances; Models, Theoretical; Sand; Soil; Soil Pollutants; Solubility; Tannins; Triazoles

Treated Rhizopora mucronata tannin (RMT) as a corrosion inhibitor for carbon steel and copper in oil and gas facilities was investigated. Corrosion rate of carbon-steel and copper in 3wt% NaCl solution by RMT was studied using chemical (weight loss method) and spectroscopic (FTIR) techniques at various temperatures in the ranges of 26-90°C. The weight loss data was compared to the electrochemical by the application of Faraday's law for the conversion of corrosion rate data from one system to another. The inhibitive efficiency of RMT was compared with commercial inhibitor sodium benzotriazole (BTA-S). The best concentration of RMT was 20% (w/v), increase in concentration of RMT decreased the corrosion rate and increased the inhibitive efficiency. Increase in temperature increased the corrosion rate and decreased the inhibitive efficiency but, the rate of corrosion was mild with RMT. The FTIR result shows the presence of hydroxyl group, aromatic group, esters and the substituted benzene group indicating the purity of the tannin. The trend of RMT was similar to that of BTA-S, but its inhibitive efficiency for carbon-steel was poor (6%) compared to RMT (59%). BTA-S was efficient for copper (76%) compared to RMT (74%) at 40% (w/v) and 20% (w/v) concentration respectively. RMT was efficient even at low concentration therefore, the use of RMT as a cost effective and environmentally friendly corrosion inhibiting agent for carbon steel and copper is herein proposed.

Topics: Copper; Corrosion; Rhizophoraceae; Sodium Chloride; Spectroscopy, Fourier Transform Infrared; Steel; Tannins; Temperature; Triazoles