Removal of Dye in Wastewater by Adsorption-Coagulation Combined System with Hibiscus sabdariffa as the Coagulant

Abstract

The conventional process to treat dye wastewater is the physicochemical treatment such as coagulation, flocculation and adsorption process. A new approach has been demonstrated to treat Congo red dye wastewater, which is the adsorption-coagulation hybrid process. Natural coagulant extracted from Hibiscus sabdariffa seeds is used as the coagulant while activated carbon is used as the adsorbent in this case study. The objective of this experiment is to study the significant factors that will affect the efficiency of dye removal. Then, the optimum conditions for the hybrid process is determined using Respond Surface Methodology (RSM). The variables are pH, initial dye concentration, coagulant dosage and adsorbent dosage while the response of experiment is the dye removal percentage. A three-level and four-variable Box-Behnken design (BBD) is used for the RSM. A total of 27 sets of experimental results is required to determine the optimum conditions. Jar test is used to conduct the experiment with the addition of coagulant and adsorbent simultaneously. Based on the regression model analysis and ANOVA, the highly significant factors that contribute to the dye removal efficiency through adsorption-coagulation hybrid process are pH of solution and initial dye concentration. The RSM results shows that the optimised process parameters for adsorption-coagulation hybrid process with Hibiscus sabdariffa seeds as the coagulant and activated carbon as the adsorbent are pH 2, initial dye concentration of 385 ppm, coagulant dosage of 209 mg/L and adsorbent dosage of 150 mg/L. The dye removal reaches up to 96.67% under optimum parameters.

Treatment of Textile Wastewater by Coagulation–Flocculation Process Using Gossypium herbaceum and Polyaniline Coagulants

“…GHC exhibited maximum color removal (90.13%) in an acidic condition (pH 5.5) when compared to the alkali condition, whereas PAC showed maximum color removal (94.38%) in an alkali condition (pH 8). Similar observation was reported for Hibiscus sabdariffa seeds used as a natural coagulant for dye removal . Trung et al examined the ability of Cassia fistula seed gum (CFG) as a coagulant in combination with synthetic PAC for the treatment of textile wastewater.…”

“…Similar observation was reported for Hibiscus sabdariffa seeds used as a natural coagulant for dye removal. [39] Trung et al [37] examined the ability of Cassia fistula seed gum (CFG) as a coagulant in combination with synthetic PAC for the treatment of textile wastewater. The authors reported that CFG supplementation has improved the process efficiency, that is, nearly 98% color removal for RB21 and 90% color removal for MB at the optimum dose of CFG 0.15 and 0.1 mL, respectively.…”

Screening the six plant species for phytoremediation of synthetic textile dye waste water

“…Decorative plants are also used for the treatment of dye wastewater as Hibiscus sabdariffa is used to treat CR dye [15]. Ipomoea hederfolia plant is reported for treatment of Scarlet red dye [5].…”

Spectral filtering experimentation on photovoltaic cells using novel bio-filter made from copper coated hibiscus-ethanol extract

“…The plant extract was obtained from Hibiscus Sabdariffa as shown Figure 1. Before this experiment, it is widely known that the hibiscus extract are used for flavours, medicinal, pharmaceuticals, agrochemicals, fragrances, treatment of wastewaters and local dyes [12][13][14][15]. The major component in the flower is the cyanidin 3-sophoroside.…”