Utilization of Agro-based Adsorbents in Binary Wastewater Treatment

The application of agro-based adsorbents is growing in the tertiary stage of the wastewater treatment process during the presence of hazardous pollutants. Dye and coffee industries are among the major wastewater pollutant sources negatively affect aquatic ecosystems and human health. The current study attempts to treat a binary mixture of crystal violet (CV) and coffee wastewater using agro-based adsorbents such as peanut hull and onion peel. The performance and efficacy of low-cost adsorbents were evaluated using parameters, including transmittance and non-purgeable organic carbon (NPOC). Batch adsorption studies were conducted to optimize both the adsorbent size and dosage that affect the treatment process. The experimental data obtained from the experiment were analyzed to understand whether Langmuir or Freundlich best fits the treatment process's experimental data. It was observed that Langmuir isotherm seems to fit experimental data using peanut hull and Freundlich isotherm using onion peel. The kinetics of the adsorption process appears to follow the pseudo-first-order kinetic model. The regression coefficient value of onion peel was 0.91, and uptake was 58.14 mg/g. Similarly, using the peanut hull, the regression coefficient was 0.99, and uptake was 57.47 mg/g. It seems that peanut hull appears to perform better as a low-cost adsorbent compared to onion peel. The adsorption capacity increased with the increasing dosage of low-cost adsorbent (peanut hull) until the adsorbent size of 0.6-0.425 mm and steadily decreased after that.

Synthetic Wastewater Treatment using Agro-Based Adsorbents

This study was undertaken to determine the treatment a binary mixture of dye wastewater (containing Naphthol Green B) and the sugar industry wastewater for removal of color. The specific treatment in the current research consists of adsorption using low-cost adsorbents and microfiltration using Whatman-41 microfilters. Considerations of this treatment process are to take the samples using batch adsorption and avoid coagulation with further dilution. Numerous runs are made, with the ideal waste samples prepared in the laboratory. As a 1st step in the study, different dye concentrations are considered using different concentrations of sugar wastewater. Samples are treated with 3 different Agro-based low-cost adsorbents (orange peel, peanut hull, and Powdered Activated Carbon (PAC)). Transmittance values for Naphthol Green B after treatment with orange peel and peanut hull are 83.12 % and 76.98 % respectively. Peanut hull has the highest transmittance of 76.98 % with < 425 µm size. Orange peel contributes to the highest transmittance of 83.12 % with a 2 g dosage. The values of transmittance after treatment with PAC are taken as the datum for the comparison of adsorption performance after treatment using orange peel and peanut hull. Peanut hull has the highest Non-Purgeable Organic Carbon (NPOC) measurement of 37.86 mg/L when mixed with 600 ppm of sugar wastewater. Similarly, when mixed with 600 ppm of sugar wastewater, orange peel contributes to the NPOC value of 35.06 mg/L. These treated samples using low-cost adsorbents can be considered as pre-treated wastewater that can be sent to municipal wastewater treatment plants. HIGHLIGHTS Orange Peel and Peanut Hull are the Agro-based low-cost adsorbents for color removal Wastewater treated with Peanut Hull has high Non-Purgeable Organic Carbon measurement Peanut hull has the highest transmittance of 76.98 % with < 425µm size Orange peel contributes to the highest transmittance of 83.12 % with a 2 g dosage Powdered Activated Carbon is considered as a reference adsorbent in this study GRAPHICAL ABSTRACT