Taguchi’s experimental design for the optimization of the defluoridation process using a novel biosorbent developed from the clamshell waste

Abstract

Developing new adsorbents from waste containing chitosan materials for defluoridation is gaining vast interest. In the current research, a new adsorbent is developed from Clamshell waste and experimental investigation is done using Taguchi’s statistical design approach with $L_{16}$ orthogonal array for process variables optimization to obtain the maximum fluoride reduction. Maximum defluoridation efficiency of 87.49% and 26.31 mg/g of sorption capacity was achieved at optimum variable values of pH 7, adsorbate initial concentration 10 mg/L, mixing period 90 min, Clamshell dose 10 g/L, and a temperature 323 K. The percentage contribution of each process variable applying ANOVA is pH 34.24% > adsorbate initial concentration 21.17% > mixing period 18.14% > Clamshell dose 15.33% > temperature 11.12%. The fluoride removal with Clamshell adsorbent followed the Freundlich isotherm and fitted well with the pseudo-second-order kinetic model. Thermodynamic parameters (ΔH = 15.075 kJ/mol, ΔS = 0.132 kJ/mol. K) reveal the sorption mechanism is spontaneous and endothermic. SEM and EDAX are used to study surface morphology and FTIR to know the functional groups on the adsorbent that participate in fluoride binding. The reusability study indicates that clamshell absorbent can be reused up to 3 regeneration cycles. The practical feasibility of using the Clamshell sorbent for fluoride removal from field water samples was found to be quite effective.

Graphical Abstract

Keywords:

• Defluoridation
• clamshell waste
• Taguchi optimization
• isotherms and kinetics
• thermodynamics

Authors contributions

Veera Brahmam Mukkanti: conceptualization, methodology, formal analysis, investigation, data curation, and writing—original draft preparation. A.R. Tembhurkar: conceptualization, methodology, investigation, and writing—original draft preparation and reviewing.

Declaration of interests

The authors report they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.