LAUSR

Abstract In this investigation, the capability of mechanochemically synthesized silver (I) coordination polymer [Ag(I)-CP] for simultaneous removal of Congo red (CR) and Indigo carmine (IC) from aqueous solutions was described. The structure of the Ag(I)-CP adsorbent was characterized by FT-IR and PXRD instrumental techniques. The significant and interaction of parameters (pH, adsorbent mass, ultrasound time and CR and IC initial concentration) on their removal efficiency were studied by central composite design (CCD) associated with response surface methodology (RSM). The maximum adsorption was obtained at variables set at pH = 6, 15 mg Ag(I)-CP, 4 min sonication time and 12 mg L−1 of both dyes at room temperature. Under the optimized parameters, an adsorption efficiency of 99.5%, with relative standard deviation of 1.7%, was obtained via five replicated measurements at center. The results indicate that the R2 values were >0.995, while the adjusted R2 (0.9992 and 0.9971 for CR and IC respectively) values are in close conformity with R2. The equilibrium data fitted better to Langmuir model than Freundlich one with minimum error, while Langmuir adsorption capacity assign to monolayer were 60.240 and 52.360 mg g−1 for CR and IC, respectively. The kinetic studies demonstrated that the adsorption process followed pseudo-second-order kinetics.