Abstract:
Globally, a ninth of people use polluted water sources because an estimated 300–400 Mt of waste and 90% of sewage are discharged
into water bodies from industries and developing countries, respectively. ,e utilisation of indigenous fruit pits in producing
novel adsorbents will greatly benefit in wastewater treatment. In most underdeveloped countries, activated carbon (AC) is
imported at a high cost. ,e study was aimed at synthesising and characterisation of AC obtained from Marula nutshell.
Carbonization of organic matter from Marula nutshell was carried out at 200°C, 400°
C, 500°C, and 600°
C. Sulphuric (H2SO4) and
phosphoric (H3PO4) acids were used as activating agents at concentrations of 20–60% (v/v). Physicochemical characteristics of the
AC, such as bulk density, moisture, ash, pH, and iodine number, were analyzed using standard methods. Functional groups and
total carbon content were determined using the FTIR spectroscopy and Nitrogen Carbon Sulphur (NCS) analyzer, respectively.
,e values of carbon yield and total carbon in activated samples with H2SO4 and H3PO4 were 32.2–93.2%, 26.9–95.8%, and
46–79%, 20.8–69.8%, respectively. ,e pH, ash, moisture, and bulk density of activated high carbon samples with H2SO4 ranged
from 2.4–6.1, 0.65–3.49%, 1.3–8.4%, and 0.42–0.62 gcm−3, respectively. Activated high carbon samples with H3PO4 had 2.7–3.2,
11.3–29.8%, 4.7–14.6%, and 0.39–0.54 gcm−3 pH, ash, moisture, and bulk density, respectively. ,e synthesised AC samples with
40% H3PO4 at 500°C had the highest iodine value of 1075.7 mg/g. FTIR results showed the presence of aliphatic carboxylic acid
salt, inorganic nitrate (NO3−
), and phosphate groups in the synthesised AC and were not significantly different (p < 0.05) from
commercial AC. ,e untreated Marula nutshell had some aliphatic hydrocarbon (alkanes), inorganic phosphate (PO3−
4 ), aliphatic
ester (–COO), and aliphatic carboxylic acid salt (–C(�O)O–) groups. A novel adsorbent, AC was produced from Marula nutshell
with the potential to be used in water treatment.
