Effects of Biochar Production Methods and Biomass Types on Lead Removal from Aqueous Solution

Granados, Paola; Mireles, Sergio; Pereira, Engil Isadora Pujol; Cheng, Chu-Lin; Kang, James Jihoon

doi:10.3390/app12105040

Cited by 15 publications

(13 citation statements)

References 40 publications

(57 reference statements)

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“…Figure 4 shows the FTIR spectra of Fe-or Mg-loaded AB overlayed with unmodified AB. Overall, all biochar displayed broad peaks (3500-3200 cm −1 ) by O-H stretching (water, H-bonded hydroxyl groups) to varying degrees, indicating the dehydration of cellulosic and ligneous components of AB [24,45]. The O-H stretching appeared to be more intense in Fe-loaded AB and less intense in Mg-loaded AB.…”

Section: Biochar Characterizationmentioning

confidence: 99%

“…Aliphatic moieties (C-H stretching at 3050 cm −1 ) were observed in unmodified AB and Fe-loaded AB (lesser extent), but the C-H stretching disappeared in Mg-loaded AB. All biochar displayed C=O stretching at 1740-1700 cm −1 , indicating carboxylic groups and traces of aldehydes, ketones, and esters [24,45]. Aromatic moieties (C=C stretching at 1600, 1510, and 1440 cm −1 ; C-H bending at 885, 815, and 750 cm −1 ) were observed in varying degrees in the fingerprint region [11,47].…”

Section: Biochar Characterizationmentioning

confidence: 99%

“…The collected seeds were rinsed with tap water, chopped in smaller sizes (1-2 cm), and oven-dried at 105 °C (Supplementary Figure S1). Dry avocado seed cuts were placed in a quartz crucible and were pyrolyzed at 400 °C in a muffle furnace for 2 h, which was found to be the optimal pyrolysis temperature for cationic heavy metal adsorption in previous studies [11,24]. The AB retained between the No.…”

Section: Biochar Productionmentioning

confidence: 99%

“…For the crystal structure of the biochar materials, X-ray diffraction (XRD) patterns were collected using a Bruker D2 X-ray diffractometer (Bruker, Billerica, Massachusetts, USA) from 10-80° in 2θ with a step of 0.05° and a 5 s counting time. The biochar's pH was measured by a pH meter (EC500, Extech Instruments, Waltham, MA, USA) in a 1:10 ratio of biochar-to-solution (DI water) after 1 h of equilibration [24]. The surface morphology of biochar samples was examined through a scanning electron microscope (SEM, ZEISS EVO LS10, Hitachi, Japan).…”

Section: Biochar Characterizationmentioning

confidence: 99%

“…Thus, making biochar using the avocado seed is an alternative way of recycling the seed waste. A recent study found that the avocado seed biochar (AB) was effective in removing aqueous lead [24].…”

Section: Introductionmentioning

confidence: 99%

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Iron and Magnesium Impregnation of Avocado Seed Biochar for Aqueous Phosphate Removal

et al. 2022

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There has been increasing interest in using biochar for nutrient removal from water, and its application for anionic nutrient removal such as in phosphate (PO43−) necessitates surface modifications of raw biochar. This study produced avocado seed biochar (AB), impregnated Fe- or Mg-(hydr)oxide onto biochar (post-pyrolysis), and tested their performance for aqueous phosphate removal. The Fe- or Mg-loaded biochar was prepared in either high (1:8 of biochar to metal salt in terms of mass ratio) or low (1:2) loading rates via the co-precipitation method. A total of 5 biochar materials (unmodified AB, AB + High Fe, AB + Low Fe, AB + High Mg, and AB + Low Mg) were characterized according to their selected physicochemical properties, and their phosphate adsorption performance was tested through pH effect and adsorption isotherm experiments. Fe-loaded AB contained Fe3O4, while Mg-loaded AB contained Mg(OH)2. The metal (hydr)oxide inclusion was higher in Fe-loaded AB. Mg-loaded AB showed a unique free O–H functional group, while Fe-loaded AB showed an increase in its specific surface area more than 10-times compared to unmodified AB (1.8 m2 g−1). The effect of the initial pH on phosphate adsorption was not consistent between Fe-(anion adsorption envelope) vs. Mg-loaded AB. The phosphate adsorption capacity was higher with Fe-loaded AB in low concentration ranges (≤50 mg L−1), while Mg-loaded AB outperformed Fe-loaded AB in high concentration ranges (75–500 mg L−1). The phosphate adsorption isotherm by Fe-loaded AB fit well with the Langmuir model (R2 = 0.91–0.96), indicating the adsorptive surfaces were relatively homogeneous. Mg-loaded biochar, however, fit much better with Freundlich model (R2 = 0.94–0.96), indicating the presence of heterogenous adsorptive surfaces. No substantial benefit of high loading rates in metal impregnation was found for phosphate adsorption. The enhanced phosphate removal by Mg-loaded biochar in high concentration ranges highlights the important role of the chemical precipitation of phosphate associated with dissolved Mg2+.

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Section: Biochar Characterizationmentioning

confidence: 99%