废砖的酸碱改性及其去除铅离子的性能研究

Study on the Acid-base Modification of Waste Bricks and Its Performance of Lead Ions Removal

使用HF和NaOH对废砖进行酸碱改性,并进一步研究了新材料的理化特性以及其对水中铅离子的吸附性能。研究结果表明,在HF浓度为0.5~3 mol/L的范围内,酸改性的砖粒比表面积变化显著,呈现先增大后减小的趋势,从原来的25.30 m^(2)/g增加到63.37 m^(2)/g然后开始减小;碱改性的砖粒,比表面积随碱的浓度增大而增大,但增大趋势不明显,仅从25.30 m^(2)/g增加到40.04 m^(2)/g。酸碱改性对砖粒的化学组成和表面功能基的影响不大。2 mol/L HF酸改性砖粒对铅离子的饱和吸附容量为93.10 mg/g比原砖粒对铅离子的饱和吸附容量50.44 mg/g提高了近1倍。改性后的砖粒吸附速率比未改性砖粒稍低。该研究表明,酸碱改性后的砖粒对水中铅离子具有较高的吸附性能,可以用于去除水中的重金属污染物,达到以废治废的目的。

In this study, HF and NaOH were used for acid-base modification of brick granules, and the physical and chemical properties of the new material and it’s adsorption of lead ions in water were further studied. The results showed that the specific surface area of the acid-modified bricks changed significantly within the range of HF concentration of 0.5~3 mol/L, with a trend of first increasing and then decreasing, from 25.30 m^(2)/g to63.37 m^(2)/g and then decreasing. The specific surface area of alkali modified brick increases with the increase of alkali concentration, but the increase trend is not obvious, only from 25.30 m^(2)/g to 40.04 m^(2)/g. Acid-base modification has little effect on the chemical composition and surface functional groups of brick. The saturated adsorption capacity of 2 mol/L HF acid modified brick to lead ions was 93.10 mg/g, which was nearly 1 times higher than that of the original brick to lead ions at 50.44 mg/g. The adsorption rate of modified brick was lower than that of unmodified brick. The study shows that the acid-alkali modified brick has a high adsorption ability to lead ions in water, which can be used to remove heavy metal pollutants in water and achieve the purpose of treating waste with waste.