Application of Modified Spent Mushroom Compost Biochar (SMCB/Fe) for Nitrate Removal from Aqueous Solution

Abstract

The public is already aware that nitrate pollution caused by nutrient runoff from farms is harmful to aquatic life and human health, and there is an urgent need for a product/technology to solve this problem. A biochar adsorbent was synthesized and used to remove nitrate ions from aqueous media based on spent mushroom compost (SMC), pre-treated with iron (III) chloride hexahydrate and pyrolyzed at 600 °C. The surface properties and morphology of SMCB/Fe were investigated using Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The effect of main parameters such as the adsorbent dosages, pH of the solutions, contact times, and ion concentrations on the efficiency of nitrate removal was investigated. The validity of the experimental method was examined by the isothermal adsorption and kinetic adsorption models. The nitrate sorption kinetics were found to follow the pseudo-second-order model, with a higher determination coefficient (0.99) than the pseudo-first-order (0.86). The results showed that the maximum percentage of nitrate adsorption was achieved at equilibrium pH 5–7, after 120 min of contact time, and with an adsorbent dose of 2 g L−1. The highest nitrate adsorption capacity of the modified adsorbent was 19.88 mg g−1.

Efficient Nitrate Adsorption from Groundwater by Biochar-Supported Al-Substituted Goethite

“…The kinetic experiment was conducted with the following conditions: the dosage of 0.2 g, the solution volume of 50 mL, the initial nitrate concentration of 50 NO 3 − -N mg/L, the initial pH of 7, the contact time of 4 h, the shaking speed of 150 rpm/min, and the solution temperature of 25 • C. During the experiment, liquid samples were analyzed at 0, 5,10,15,25,35,50,65,80,100,150,200,300, and 400 min, respectively.…”

“…Recently, more interest regarding the adsorptive removal of nitrate from water has been paid to biochar-based adsorbents [15][16][17]. Biochar refers to a carbon-rich material generated from the pyrolysis process (heating in the absence or limited supply of oxygen) of biomass.…”