Study area
The study was carried out at biomedical research Laboratory of Ahfad University for Women at Omdurman in Khartoum state (Sudan).
Sample collection and preparations:
Two samples of MS and DS were used to carry out these experiments. Mango and date were brought from the local market (Sug El Arabi).
The seeds and the stones were taken from the fruit.They were cleaned, removed from the foreign materials then ground to a powder using an electric grinder to pass a 0.5 mm screen.
The general process to produce activated carbon is based on carbonizing and activating the carbon aqueous precursor or material. Stones of dates and mango seeds are collected and cleaned.The two products as natural as they were, were crushed by mortar and pistil to a fine powder (size 0.5 mm). The powder was put in crucible, and 1 g of zinc chloride was added to it. It was incinerated at 350 °C for not less than 3 h in an oven. It was cooled in a room temperature. The resulting ash was considered as activated carbon. This activated carbon was used in solubility test, pH, carbon content, ash content, moisture content and reduction of methylene blue.
Seventy ml of concentrated HCl was measured and added to 550 ml of distilled water and mixed well, 12.7 g of KOH crystal was taken and dissolved in 250 ml of distilled water, 0.1 g of methylene blue powder was taken and dissolved in 100 ml of distilled water.
A filter paper was used to filter all the mixture of water and activated carbon samples, filter paper and its glass wear set were cleaned well, the filtration was done once time and the clear solution was carefully collected for analysis (Awe et al.2020; Zheng et al.2018).
Physical and chemical methods of adsorbent
The general process to produce activated carbon is based on carbonizing and activating the carbonaceous precursor material. Stones of dates and mango seeds are collected and cleaned.The two products as natural as they were, were crushed by mortar and pistil to a fine powder (size 0.5 mm). The powder was put in crucible, and 1 g of zinc chloride was added to it. Then it was incinerated at 350 °C for not less than 3 h in an oven. It was cooled in a room temperature. The resulting ash was considered as activated carbon. This activated carbon was used in solubility test, pH, carbon content, ash content, moisture content and reduction of methylene blue.
The methods described by Zhang et al. (2005), Chen et al. (2002) and Bernal et al. (2018) were used to measure the physical and chemical properties of the activated carbon produced.
pH
pH was measured by suspending 1 g of carbon from each sample into a 100 ml glass beaker, 25 ml of distilled water was added and boiled on the hot-plate for 5 min. Then cooled the decanted portion to room temperature and measured by using pH meter (HACH 103).
Moisture content
Half gram from activated carbon was weighed into a pre-dried weighing crucible with lid, close and weight at once to the nearest 0.5 g. The lid was removed and placed the container and lid in a preheated forced circulation oven at 105 °C. The oven was closed and dried to constant weight. Cooled in desiccators to ambient temperature and weight.
$${\text{M}}_{{\text{n}}} = \, \left( {\left( {{\text{W}}_{{\text{w}}} - {\text{W}}_{{\text{d}}} } \right)/{\text{W}}_{{\text{w}}} } \right) \, \times { 1}00$$
in which: Mn = moisture content (%) of material, WW = weight of the sample before drying, Wd = weight of the sample after drying.
Ash content
The crucible was ignited in the muffle furnace at 650 °C for 1 h. The crucible was placed in the desiccators. It was cooled to room temperature and was weighed out to the nearest 1 g from activated carbon of each sample and was put into ignited separated crucible in muffle furnace at 650 °C. Ashing can be considered complete when constant weight is achieved. The crucible was placed in the desiccators, and cooling was allowed to room temperature. When it was cooled, air was admitted slowly to avoid loss ash from the crucible and was weighed.
$${\text{Ash}}\,\left( \% \right) \, = \frac{{{\text{Final}}\,{\text{solids}}\,{\text{weight}}\,\left( {\text{g}} \right) }}{{{\text{Initial}}\,{\text{carbon}}\,{\text{weight}}\,\left( {\text{g}} \right)}} \times 100$$
$${\text{Ash}}, \, \% \, = \left( {{\text{W1}}/{\text{W2}}} \right) \times {1}00$$
where: W1 = weight of ash, W2 = initial weight of dried sample.
