Table 1.
A comparison between the performances of DPs prepared in the current approach and as reported in literature.
| Adsorbent (DPs)* | Modification Method | Analytical approach used | HM removed | BET surface area and pore volume | Adsorption Capacity (mg/g) | Adsorption/ removal (%) | References |
|---|---|---|---|---|---|---|---|
| Untreated date pits | Samples were washed, dried for 2 h at 125°C, crushed and then sieved with size (25–63 μm) | Univariate analysis | Pb (II) | ND | 2.89 mg/g | 95% | Samra et al., 2014 |
| Raw and activated date pits;RDPADP | Date pits were washed and dried at 80°C for 2 h, crushed, grinded and sieved in a sieve series 60-mesh. For ADP; powder was mixed with 85% phosphoric acid in weight ratio 1:3 and heated to 160°C | Univariate analysis | Cu (II) Cd (II) |
ND |
Cu(II) RDP: 7.40 mg/g ADP: 33.44mg/g Cd(II) RDP: 6.02 mg/g ADP: 17.24mg/g |
96.67% | Hilal et al., 2012 |
| RDPPDP100, 24KOH-DPACDPAC | The seed powder was washed and dried at 120°C for 8 h. Then the powder was soaked with 85% H3PO4 with ratio of 1:2.5. After 12 h. of impregnation, the filtered date pits powder was subjected to carbonization in a muffle furnace at 650°C for 120 min | Univariate analysis | Pb (II) |
RDPP: 0.027 m2/g, and 0.255 cm3/g DPAC: 316.9 m2/g, and 1.167 cm3/g |
10.53 mg/g 31.69 mg/g 55.27 mg/g 115.83 mg/g |
99.4% | Krishnamoorthy et al., 2019 |
| Activated carbon of date pits;AC1AC2AC3 |
AC1: DP, Steam/N2, 1 h at 700°C. AC2: Date pits, steam, calcium acetate, 1 h at 700°C. AC3: Date pits, pure steam, 1 h at 800°C |
Univariate analysis | Co (II) Fe (III) Pb (II) Zn (II) |
AC1: 0.0188 m2/g, and 0.095 cm3/g AC2: 0.029 m2/g, and 0.248 cm3/g AC3: 0.0702 m2/g, and 0.321 cm3/g |
(AC3) Co (II): 1,317 mg/g Fe (III): 1,555 mg/g Pb (II): 1,261 mg/g Zn (II): 1,594 mg/g |
95% | Awwad et al., 2013 |
| Untreated date stones (D.S) | Dates were washed with water, dried for 24 h at 105°C, crushed and sieved with size (1 mm) | Univariate analysis | Cr (VI) | 1.2 m2/g, and 0.02 cm3/g |
Free pH: 18.2 mg/g pH (2): 70 mg/g |
ND | Khelaifia et al., 2016 |
| Untreated date pitsRDP | Dates were washed, dried for 24 h at 70°C, crushed and sieved with size (250 μm) | Univariate analysis | Au (III) | M.B. adsorption method: 285 m2/g | With 0.5 M HCl: 78 mg/g | 90% | Al-Saidi, 2016 |
| Current approach | |||||||
| RDP | Please see the experimental section | Multivariate analysis | Cu(II) | RPP: 2.72 m2/g and 0.007987 cm3/g | ND 4.036 mg/g |
47.65% | |
| BDP | Please see the experimental section | BPP: 158.1 m2/g and 0.136163 cm3/g | 98.51% | ||||
*
Adsorbent (DPs) given names and abbreviations are as mentioned in the corresponding reference. ND, not determined.