Adsorption characteristics of ammonium onto biochar from an aqueous solution

Abstract

Ammonium contamination in water is a major concern worldwide. This study focuses on the removal of ammonium from aqueous solution by batch adsorption experiments using biochar derived from a combination of various wood chips (spruce, pine, and fir). Adsorption characteristics of ammonium onto biochar were evaluated as a function of biochar dosages, initial concentrations of ammonium, contact time and pH. Results demonstrated that ammonium removal increased with the increase of biochar dosage. The percentage of ammonium removal reached a value of 80% at a biochar dosage of 100 g/L. Ammonium removal decreased by 15% with the increase of initial ammonium concentration by 50 mg/L. The optimum pH for ammonium removal was considered in the range from 6 to 8. Ammonium removal reached its stable value within 3 days. The maximum adsorption capacity of ammonium was 0.96 mg/g for 80 mg/L of initial ammonium concentration. The adsorption isotherm followed both the Langmuir and Freundich models for ammonium adsorption onto biochar. Fourier Transform Infrared (FTIR) spectroscopy results indicated the presence of amine, amide and nitrile functional groups on the surface of biochar which could contribute to the adsorption of ammonium onto biochar. Thus, biochar derived from various wood chips showed the potential to remove ammonium from aqueous solution.

Evaluation of NH 4 + Adsorption Capacity in Water of Coffee Husk-Derived Biochar at Different Pyrolysis Temperatures

“…is finding was also mentioned by Gao et al who studied the ammonium adsorption capability of biochar from peanut shells, corn cobs, and cotton tree trunks at 300, 450, and 600°C and kept in 2 hours [33]. e study's result matched with the work of of Begum et al of pyrolyzed woodchips at 700°C whose result was 0.96 mg.g −1 [32].…”

“…e data (Figure 2, Table 3) showed that Langmuir and Freundlich models were suitable to describe the NH + 4 adsorption, with R 2 greater than 0.95 in all the 3 biochars, and maximum adsorption values are 1.5, 1.2 and 0.9 mg g −1 , respectively, to 300, 450, and 600°C biochar, which fitted the experiment values. Other studies also reported that the ammonium adsorption onto some biochars followed both the Langmuir and Freundlich models [32,33]. R 2 values of the Langmuir model were 0.97, 0.95, and 0.96, respectively, which were slightly less than those of the Freundlich model, 0.97, 0.99, and 0.97, respectively.…”

Ammonium removal by alkaline‐activated coconut coir from synthetic and ground waters

“…The NH 4 + adsorption capacity ( q ) of NaACC was determined to vary between 0.60 and 0.92 mg/g (Figure 2c). The ammonium adsorption efficiency increased with the increase of NaACC material is attributed to the increase number of active adsorption sites due to the increase of the adsorbent in the synthetic water solution 54 . However, this increase trend is limited to a certain level of adsorbent dose.…”

“…The ammonium adsorption efficiency increased with the increase of NaACC material is attributed to the increase number of active adsorption sites due to the increase of the adsorbent in the synthetic water solution. 54 However, this increase trend is limited to a certain level of adsorbent dose. The decrease in ammonium adsorption efficiency was found when the adsorbent dosage was increased over the certain value due to increase of mass transfer resistance of ammonium ions to the active surface of absorbent.…”

Effects of substrate types on nitrogen removal efficacy and growth of Canna indica L.

“…Biochar has a negative charge and high CEC, so its properties are beneficial for NH4 + adsorption [50]. Many previous studies showed high efficiency of biochar on NH4 + adsorption [51][52][53]. Also, pumice containing -OH groups is suggested for use as an adsorbent [54].…”