Removal of acid red 88 from wastewater by adsorption on agrobased waste material. A case study of Iranian golden Sesamum indicum hull

Abstract

Background: Colors are very useful in different industries such as textile and leather but when they enter water, can cause many biological and environmental problems. In the present research, a waste agricultural material which is freely available is employed to analyze its efficiency for removing acid dye from contaminated wastewaters. Methods: In this study, batch adsorption experiments were performed in the treatment process of acid red 88 (AR88) by Iranian golden Sesamum indicum (IGSI) seeds hull which is produced abundantly in some countries and especially in Iran up to 1100 kg/ha. Also, the effect of operational parameters like adsorption time, pH, dye concentration and adsorbent dosage was studied on pollutant removing efficiency. The experimental data of AR88 adsorption was fitted to Langmuir, Freundlich and Temkin isotherm models. The scanning electron microscopy (SEM) images for the IGSI were taken before and after adsorption process. Results:The efficiency of dye adsorption on adsorbent was found to be 98.2%. The optimum pH for treatment was 4.5 which is in the acidic range. Enhancing the adsorbent dosage from 0.5 to 2.5 g caused increasing in removal efficiency from 73.85% to 95.85%. Decreasing in dye concentration from 70 to 30 mg/L caused increasing in removal efficiency from 79.73% to 95.83%. The process of adsorption was best fitted to Langmuir model and the amount of dye adsorbed on adsorbent, q e , was found to be 25 mg/g. Comparison between SEM images before and after dye adsorption, showed the significant difference that was due to the dye loading on adsorbent. Conclusion:The results of present study demonstrated higher dye removal efficiency for AR88 in acidic pHs. Employing the IGSI material in this study proves to be a potential alternative to expensive adsorbents, utilized for the treatment of contaminated industrial waste waters. Keywords: Adsorption, Acid red 88, Waste products, Sesamum, Waste water, Color removal Citation: Zarei M, Pezhhanfar S, Ahmadi Someh A. Removal of acid red 88 from wastewater by adsorption on agro-based waste material. A case study of Iranian golden Sesamum indicum hull.

Removal of direct blue 129 from aqueous medium using surfactant-modified zeolite: a neural network modeling

“…According to the assumption of the Langmuir isotherm model, the adsorption of DB129 onto modified zeolite occurred as a monolayer on the surface. A similar observation was reported for the adsorption of acid red 88 on Iranian golden Sesamum indicum hull (19), Congo red on rice husk (42) and methylene blue on pineapple stem waste (43).…”

“…After mixing, zeolites were washed with distilled water, passed through the appropriate filter and dried at 105°C for 12 hours (18). The experiments were performed according to Zarei et al (19). 400 mL graduated cylinder containing 100 mL dye solution was utilized, in which the adsorbent was added.…”

Removal of Acid Orange 7 dye from aqueous solutions using polyaniline-modified rice bran: isotherms, kinetics, and thermodynamics

“…The correlation coefficients of five isotherm models under study (Figure 7) shows that the Langmuir isotherm, with a correlation coefficient of 0.9864 is the most suitable model for the adsorption of AO7 using RB/PANI adsorbent. Since the Langmuir isotherm is only valid for the adsorption of adsorbate in aqueous solutions by bioadsorbents with limited number of unified sites in a single layer, it can be concluded that AO7 dye is adsorbed by RB/ PANI in a single layer and relatively monotonous state (40). Based on the results of Table 3, there is a significant difference between the equilibrium adsorption capacity (q e (exp) ) and calculated equilibrium adsorption capacity (q e (cal) ) for pseudo-first-order model.…”