Analytical Method to Monitor Industrial Pickling Baths Initially Constituted by HF, HNO₃

The present study couples the acid/basis titration and the ICP analysis in order to monitor the concentrations of nitric and hydrofluoric acids, and presents into baths used to pickle alloys of titanium or stainless steel, largely employed in the aeronautic industry. The pickling of the alloys releases various metallic cations able to react with HF in order to lead to metal-fluoride complexes and free H+, the last being able to react with the basis. In this study, it was determined: the most significant correlations providing the number of the protons released by the complexation of the metallic cation by the fluoride. The proposed method based on: 1) these correlations;2) the titration pH = f(VKOH) curves;and 3) the content of metallic cations determined by ICP, enables the monitoring of the content of HNO3 and HF into the pickling bath. Assuming that one bath was used for one type of alloy (alloys of Titanium for example, or alloys of stainless steel), then the proposed method appears providing reliable concentration values of both acids as well as metallic cations.

生物质基官能化碳纳米管的制备与表征

采用AAO模板法制备生物质基碳纳米管.通过“H2SO4+HNO3”混合酸回流氧化,制得官能化生物质基碳纳米管.运用FT-IR、SEM、Raman等测试技术对新型碳材料的结构和形貌进行表征.实验结果表明,在水浴温度80℃,“H2SO4+HNO3”混合酸Ⅰ条件下回流2h,得到的产品羧基含量较多,碳纳米管形貌破坏较少.混合酸氧化工艺可以在碳纳米管表面引入羧基、羰基和羟基等官能团,优化碳纳米管的功能特性,拓展其在催化材料中的应用.