Adsorption of Cd(II) from aqueous solutions by rape straw biochar derived from different modification processes

Removal of cadmium(II) cations from an aqueous solution with aminothiourea chitosan strengthened magnetic biochar

“…The variation of pH before and after the addition of adsorbent in Figure (b) proved that the adsorbent surface protonation and deprotonation process occurred during the adsorption process . Researchers reported that the Cd(II) adsorption efficiencies became steady after the solution pH was greater than 5 in the application of pristine rape straw BC and various modified BCs as adsorbents, respectively. The Cd(II) adsorption amount of MBC (5.76 mg/g) in this study was a bit lower than that of the reported BC–FeO x (>9 mg/g) .…”

“…We found that the zero point of charge (pH zpc ; ΔpH = 0) of TMBC was around 7, whereas the pH zpc values of BC and MBC were all above 8 [Figure (b)]. The variation of pH before and after the addition of adsorbent in Figure (b) proved that the adsorbent surface protonation and deprotonation process occurred during the adsorption process . Researchers reported that the Cd(II) adsorption efficiencies became steady after the solution pH was greater than 5 in the application of pristine rape straw BC and various modified BCs as adsorbents, respectively.…”

“…Researchers reported that the Cd(II) adsorption efficiencies became steady after the solution pH was greater than 5 in the application of pristine rape straw BC and various modified BCs as adsorbents, respectively. The Cd(II) adsorption amount of MBC (5.76 mg/g) in this study was a bit lower than that of the reported BC–FeO x (>9 mg/g) . The difference might have been due to the fact that the various iron oxides had different affinities to the contaminants, and the amorphous iron oxide had a higher affinity to the contaminant than the fine Fe 3 O 4 crystal particles .…”

One-pot activation and pyrolysis of Moroccan Gelidium sesquipedale red macroalgae residue: production of an efficient adsorbent biochar

“…The presence of aromatic rings was proven by the presence of bands at approximately 1570-1590 cm −1 that reflect vibrations in condensed aromatic carbon skeletons (Zhang et al 2014), and they occurred in AcBC-NaOH (2.5 wt%), AcBC-H 3 PO 4 (2.5 wt%), and AcBC-KOH (5 wt%). However, the peak observed at 1430 cm −1 can be assigned to bending vibrations of C-H aliphatic bonds (Li et al 2017). Although, there was a positional shift for all of the activated biochars, which was probably due to the carbonization process (González et al 2013).…”

“…The peak around 1035-1050 cm −1 which is detected for AcBC-KOH (2.5 wt%), and AcBC-NaOH (2.5 wt%) corresponds to the angular deformation in plane of C-H bonds of the aromatic rings (Zhu et al 2018). While, the peaks around 1143 cm −1 correspond to C-O stretching vibration of esters bonds (Li et al 2017). An exception for Table 2 Surface functional groups of AG (algae residue), BC (unactivated biochar), and various prepared AcBC (activated biochar) detected by FTIR analysis AcBC-H 3 PO 4 (2.5 wt% and 5 wt%) is that they showed a peak at 1076 and 1082 cm −1 which is ascribed to the symmetrical vibration in chain of P-O-P (Polyphosphate) (Puziy et al 2002).…”