Adsorptive Removal of Hexavalent Chromium by Diphenylcarbazide-Grafted Macadamia Nutshell Powder

Table 4

Comparison of adsorption capacities.

Adsorbents	Pretreatment	Functionalization	pH	(mg/g)	References
Potato peels	HCl	—	2.5	3.28	[45]
Raw rutin	Extraction/isolation	—	3	26.3	[34]
Rutin resin	Formaldehyde/HNO3	—	3	41.6	[34]
Banana peels	HCl/NaOH/H2O2	Acrylonitrile grafted	3	6.17	[31]
Palm branches	H2SO4	—	2	25	[32]
Palm branches	Acetic acid	Chitosan	6	55	[32]
Palm branches	H2SO4	Cationic surfactant	6	41.7	[32]
Grape peelings	H2O2	—	5.5	39.06	[7]
Banana peels	—	—	5	3	[15]
Orange peels	—	—	3	9	[15]
Coir pith	—	Acrylic acid	2	165	[16]
Masau stones	NaOH	Epichlorohydrin/diethylenetriamine	3.5	87.33	[19]
Coir pith	—	Acrylic acid	2	196	[16]
Macadamia nutshell	H2O2	—	1	37.74	This study
Macadamia nutshell	H2O2	Diphenylcarbazide	1	72.12	This study