Adsorption of Cu(II) and Zn(II) onto Activated Carbon from Oil Palm Empty Fruit Bunch Prepared by Two-Step Acid Treatment and Microwave-Assisted Pyrolysis

Table 6

Adsorption capacity of activated carbon with various raw materials toward heavy metals.

Heavy metal	Raw material	Adsorbent dose (g/L)	pH	(mg/g)	Best fit isotherms model	Reference
Cu(II)	Tahiti lemon peels	—	—	28.85	Langmuir	[36]
	Green vegetable waste	0.6	3.5	75.0	Langmuir	[37]
	Water hyacinth	12	6	3.53	Langmuir	[38]
	Pomelo peels	0.25	5	151.35	Langmuir	[39]
	Sugarcane bagasse	2	4.5	225	Langmuir	[40]
	Sewage sludge	0.5	5	26.06	Langmuir-Freundlich	[41]
	Banana leaves	2	5	66.2	Langmuir	[42]
	Calcium-rich biochars	1	5	141.76	Langmuir	[43]
	Raw cow manure	1.25	5	41.83	Freundlich	[44]
	Henna leaves	1.2	7	3.65	Langmuir	[45]
	Agricultural waste	3	9	56.2	Freundlich	[46]
	Oil palm empty fruit bunch	1	5	44.29	Langmuir	This study
Zn(II)	Coconut shell based	1	12	7.87	Langmuir	[47]
	Macadamia nutshell	0.3	4	22.73	Langmuir	[48]
	Water hyacinth	12	6	9.42	Langmuir	[38]
	Chlorella sp.	0.5	6	24.76	Langmuir	[49]
	Palm kernel shell	15.5	5	44.8	Langmuir	[50]
	Oil palm empty fruit bunch	1	5	36.43	Langmuir	This study