Removal of Phenolic Compounds using Compost from Chicken Manure and Cardboard as Bulking Agent: Adsorption Tests and Cost Analysis

Abstract

Recently, there has been increased interest in the use of composting to develop bioadsorbents for different pollutants. In this work, the removal of phenol, 2-nitrophenol, and 2,4-dinitrophenol from water is examined using compost derived from chicken manure (C/N ratio 6.3) and cardboard (C/N ratio 202.2) as a low-cost bulking agent. Characterization of the compost indicated its maturity, stability, and the presence of diverse surface functional groups. Toxicity Characteristic Leaching Procedure indicated that the bioavailability of toxic heavy metals including Cr, Pb, Cd, Zn, and Cu was negligible and below the regulated limits. Following a univariate experimental design, the effect of a number of operational factors on phenol adsorption by compost was assessed. The optimum operational factors for removing phenolic compounds are compost dosage 6.0 g L−1, pH 2.0, contact time 80.0 min, and temperature 35.0 °C. The adsorption rate was adequately described using the pseudo-second order model, with relatively high estimated adsorption rates, 0.52–0.97 mg g−1 min−1. Adsorption curves of phenols were adequately presented by the Langmuir model with maximum uptake capacity of 111.0 mg g−1 for phenol, 125.0 mg g−1 for 2-nitrophenol, and 134.0 mg g−1 for 2,4-dinitrophenol, comparable to other expensive adsorbents such as activated carbon, metal–organic frameworks or nano-adsorbents. The higher removal capacity of 2-nitrophenol and 2,4-dinitrophenol over phenol is attributed to higher solubility of phenol in water and the involvement of -NO2 group in H-bonding with carboxylic group-rich-surface. The estimated production cost of compost is 0.04 USD per kg and 0.035 US Cent is needed to remove 1.0 g phenol from water.