Black Plum (Syzygium Cumini) Seeds Adsorbent for Underground Water Nitrate Attenuation and Statgraphics Optimization

Abstract

Nitrate (NO₃^–) pollution of water sources are a global issue, and gets transformed into nitrite (NO₂^–) when in contact with the saliva, resulting in a significant health implication. Groundwater from Tandari Budum, Maiduguri, Nigeria, was denitrified in this study by varying the black plum seed (BPS) adsorbent dosage, contact time, temperature and pH in the range of 0.1-1.0g, 20-140 min, 30-90℃ and 5-11, respectively. From the Draper-Lin small composite design (DSCD) 18 runs optimization studies on NO₃^– concentration and adsorption capacity () responses carried out, it was found that time and temperature have the most impact on the process. For NO₃^– reduction to 45 mg/L maximum value, optimal factors were 60℃, 80-85 min, pH = 8 and 0.4g dose; whereas for  (13.7 mg/g), it is pH = 8, dose = 0.4g, 20 min time and 39℃. There was an observed slight similarity (in the optimal outputs), differences (in the optimal factors) and discrepancies in results obtained from non-standardized experimental runs conducted initially when compared with the DSCD design of experiment (DOE). But then, the Statgraphic Centurion 19-X64 v. 19.6.04 software analysis gave a more reasonable findings, which fits a quadratic model at R² = 0.9295 (predicted NO₃^– reduction) and 0.9068 (estimated ). Since an alkaline pH, shorter time, moderate temperature and little resources are needed to attenuate NO₃^– (initially at 123 mg/L) from Tandari Budum groundwater, BPS is a novel adsorbent discovered in this study, corresponding to 63.41% removal efficiency.