Table 1.

Factors affecting the adsorption process for manganese removal.

Adsorbent	Manganese removal (%)	pH	Contact time (min)	Particle size (μm)	Adsorbent dosage (g)	Temperature (oC)	Manganese concentration (mg/L)	References
Biochar	>80	6	180	-	0.25	24.85	8 mg/L	(Idrees et al., 2018)
Rice husk ash	100	3	100	300	0.5	30	3.8 mg/L	(Adekola et al., 2016)
Peanut husk	100	6	180	-	5	25	20 mg/L	(Abdelfattah et al., 2016)
Sunflower seed shell	81.6	8	120	-	0.15	-	-	(Feizi and Jalali, 2015)
Potato peel	79.8	7	120	-	0.15	-	-	(Feizi and Jalali, 2015)
Canola flower	81.8	8	200	-	0.15	-	-	(Feizi and Jalali, 2015)
Walnut shell	96.5	8	200	-	0.15	-	-	(Feizi and Jalali, 2015)
Polyvinyl alcohol/chitosan (PVA/CS)	84.5	5	120	0.158	0.8	30	20 mg/L	(Abdeen et al., 2015)
Untreated banana peel (UTBP)	>80	6	60	-	4	25	10 mg/L	(Ali and Saeed, 2015)
Sugarcane bagasse	99	4.5	-	25–30	15	23	12 mg/L	(Esfandiar et al., 2014)
White rice husk ash	26.6	7	480	50	2.5	34.85	100 mg/L	(Tavlieva et al., 2015)
Tamarind fruit shell	74	3	60	-	1.2	30	0.1 g/L	(Bangaraiah, 2018)
Yam peel	30.5	6.8	120	106	1	30	50 mg/L	(Isagba et al., 2017)
Orange peel	96	6	-	-	-	45	300 mg/L	(Surovka and Pertile, 2017)
Modified tangerine peel	92.48	5	30	-	0.3	30	-	(Abdić et al., 2018)
Moringa oleifera seed	95	4–6	5	500–1000	0.5	-	4 mg/L	(Marque et al., 2013)
Corn cob and Strychnous Potatorum seed powder	99.8	5	60	-	0.4	40	10 mg/L	(Kumar et al., 2018)
Tea waste	95.5	-	60	-	3	-	2.2 mg/L	(Badrealam et al., 2019)
Grafted banana peels (GBPs)	94	7	60	-	4	25	400 mg/L	(Ali, 2017)
Peanut husk	61	-	240	-	-	25	-	(Zaini et al., 2019)
Banana peels	97.4	5	120	-	0.8	25	20 mg/L	(Mahmoud, 2014)
Sugarcane Bagasse	62.5	6	150	750	1.5	30	2 mg/L	(Ahmed et al., 2015)
Beet pulp	86.4	6	90	750	1	30	2 mg/L	(Ahmed et al., 2015)
Moringa oleifera seed pods (MSP)	>40	8	60	100	1	35	3 mg/g	(Maina et al., 2016)
Sclerocarya birrea nut shells (MNS)	>40	8	120	100	2	35	3 mg/g	(Maina et al., 2016)
Unripe plantain peels	>32	6	60	-	2	-	50 mg/L	(Leizou et al., 2018)