Mihayo David, Vegi Maheswara Rao, Vuai Said Ali Hamad
The Department of Chemistry, College of Natural and Mathematical Sciences, The University of Dodoma, Dodoma, P. O. Box: 259, Tanzania.
Heliyon. 2022 Jul 19;8(8):e10004. doi: 10.1016/j.heliyon.2022.e10004. eCollection 2022 Aug.
The prevalence of nitrate in potable water is a serious environmental concern. Several methods for eliminating nitrate from water have been made and implemented. During the course of this research, raw (RADFP) and surface-modified fruit pericarp (SMADFP) biosorbents derived from the plant were applied in order to remove nitrate from an aqueous solution. The external features of the biosorbents were studied with the aids of SEM and BET. The FT-IR spectrometer was utilized for identification of the functional groups of the adsorbents. A UV-Vis device was used to quantify the nitrate concentration. The adsorbents under investigation exhibit a heterogeneous pore structure with a considerable number of mesopores, with surface areas of 361.527 and 379.877 m per gram for RADFP and SMADFP, respectively. FT-IR spectra revealed the presence of carboxyl, hydroxyl, carbonyl, and halogen groups on the adsorbent. The maximum nitrate removal efficiencies of RADFP and SMADFP were 64.55 and 88.95%, respectively. The maximum adsorption efficiencies are achieved when the pH is 2, the starting concentration is 27.50 mg/L, the contact period is 75.00 min, and the amount of biosorbent is 5.50 g. RADFP and SMADFP have a removal capacity of 12.45 as well as 25.18 mg per gram and adsorption intensity of 3.2300 and 5.4500, respectively. The investigational values for the elimination of nitrate ions concurred well to both Freundlich and Langmuir models with R values of 0.99917 and 0.99763 for RADFP and SMADFP, respectively, and pseudo-second-order kinetic model with R values of 0.99817 and 0.99947, respectively for RADFP and SMADFP. It can be concluded that SMADFP is a relatively better biosorbent than RADFP, which will be utilizable for the remediation of nitrate from an aqueous solution.
饮用水中硝酸盐的普遍存在是一个严重的环境问题。已经提出并实施了几种从水中去除硝酸盐的方法。在本研究过程中，应用了源自该植物的原始（RADFP）和表面改性的果皮（SMADFP）生物吸附剂，以从水溶液中去除硝酸盐。借助扫描电子显微镜（SEM）和比表面积分析仪（BET）研究了生物吸附剂的外部特征。利用傅里叶变换红外光谱仪（FT-IR）鉴定吸附剂的官能团。使用紫外可见分光光度计（UV-Vis）对硝酸盐浓度进行定量。所研究的吸附剂呈现出具有大量中孔的非均相孔结构，RADFP和SMADFP的比表面积分别为每克361.527和379.877平方米。傅里叶变换红外光谱（FT-IR）显示吸附剂上存在羧基、羟基、羰基和卤素基团。RADFP和SMADFP对硝酸盐的最大去除效率分别为64.55%和88.95%。当pH值为2、初始浓度为27.50毫克/升、接触时间为75.00分钟且生物吸附剂用量为5.50克时，可实现最大吸附效率。RADFP和SMADFP的去除容量分别为每克12.45和25.18毫克，吸附强度分别为3.2300和5.4500。对于硝酸盐离子的去除，研究值与Freundlich和Langmuir模型均吻合良好，RADFP和SMADFP的R值分别为0.99917和0.99763，与伪二级动力学模型的R值分别为0.99817和0.99947。可以得出结论，SMADFP是一种比RADFP相对更好的生物吸附剂，可用于从水溶液中修复硝酸盐。
