Adsorption of semisoft pollutants onto Bi2S3/Ag2S-AC under the influence of ultrasonic waves as external filed

Abstract

The Bi2S3–Ag2S nanocomposite loaded activated carbon (Bi2S3–Ag2S-AC) as semisoft adsorbent was prepared, characterized by FE-SEM, XRD, EDX and DRS and subsequently was used for simultaneous semisoft adsorption of ponceau-4R (P-4R) and auramine-O (AO) dyes from aqueous solution under ultrasonic waves. The influence of operational parameters such as Bi2S3–Ag2S-AC mass, AO concentration, P-4R concentration, pH and sonication time on ultrasound-assisted semisoft adsorption efficiency was studied by central composite design (CCD). Maximum ultrasound-assisted semisoft adsorption efficiencies of 99.51% and 100% were obtained at optimum conditions set as at: 10.59mgL−1 AO and 17.59mgL−1 P-4R, pH 4, 0.015g of Bi2S3/Ag2S-AC and 3.82min sonication time. In ANOVA the F-value of 269.51 and 247.84 are evidence for significance of the selected model and the lack-of-fit of P-value (0.7208 and 0.7204) is non-significant, confirming the model are statistically logic, for AO and P-4R, respectively. Results revealed that high amount of pollutants were removed from aquaes solution in presens of ultrasonic waves as external filed in short time. Isotherm studied results showed that the Freundlich and Langmuir model were appropriate to describe the ultrasound assisted semisoft adsorption behaviour of AO and P-4R dyes, respectively. Bi2S3/Ag2S-AC revealed the high ultrasound assisted semisoft adsorption capacity of 202.43 and 191.57mgg−1, for AO and P4R dyes, respectively. The results showed that pseudo-second-order model is the best model for describe kinetic behavior of the ultrasound assisted semisoft dyes adsorption onto Bi2S3–Ag2S-AC as efficient semisoft adsorbent.