Open AccessBinary Adsorption Studies of Toxic Metal Ions of Lead and Copper from Aqueous Solution by Modified Foeniculum vulgaris Seeds (Fennel Seeds)
Author(s) -
Ntandokazi Mabungela,
Ntaote David Shooto,
Fanyana M. Mtunzi,
Eliazer Bobby Naidoo
Publication year - 2021
Publication title -
asian journal of chemistry/asian journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.145
H-Index - 34
eISSN - 0975-427X
pISSN - 0970-7077
DOI - 10.14233/ajchem.2021.23223
Subject(s) - chemistry , adsorption , aqueous solution , copper , metal ions in aqueous solution , nuclear chemistry , metal , base (topology) , inorganic chemistry , organic chemistry , mathematical analysis , mathematics
Discharge of copper(II) and lead(II) ions into rivers and streams by industries and other human activitieshas gained serious consideration from regulatory bodies. These toxic metals are harmful to humanbeings and aquatic life when in high concentrations. Therefore, their removal from wastewater is veryimportant. Hence, this work reports the binary adsorption of toxic metal ions of Cu(II) and Pb(II) fromaqueous solution by pristine and modified fennel seeds. Pristine fennel seeds (PFS) were treated withacidic and alkaline solutions to develop modified adsorbents designated ATFS and BTFS, respectively.SEM images revealed that PFS had an amorphous surface with irregular cavities. However, upon acidand base treatment, the surface was more refined. The ATFS had interconnected pores while BTFShad somewhat honeycomb pores. The UV-Vis results confirmed that some of the components wereremoved from PFS during acid and base pre-treatment. FTIR spectra revealed that the adsorbents hadfunctional groups such as (-OH) and (-C=O), which were involved in the uptake of the metal ions. Itwas observed that the uptake of Cu(II) and Pb(II) ions onto all adsorbents progressively increasedwhen the initial concentration of the solution was increased. The maximum adsorption capacity wasobtained when the initial concentration of the solution was 100 mg/L. The uptake of Cu(II) and Pb(II)on PFS was 3.345 and 11.524 mg/g. While for ATFS 3.78 and 13.07 mg/g and BTFS 8.143 and 14.85mg/g, respectively. It was observed that the isotherm data fitted Freundlich better for the uptake ofboth metal ions onto all adsorbents. It was observed that there was a rapid uptake when contact timeincreased from 5 to 60 min. However, when time increased above 60 min the uptake stabilized andreached equilibrium this was due to the saturation of active sites on the surface for all adsorbents. Thekinetics study revealed that PSO fitted the data better than PFO. IPD data revealed that the uptake ofmetal ions was controlled by the synergistic of ESA and EPA. The ΔHº values for Cu(II) and Pb(II)uptake onto all adsorbents were all negative. This suggested that the reactions were exothermic.