Abstract:
Heavy metals contamination in drinking water is of great concern because of their toxicity and nonbiodegradability. Therefore, their removal is paramount. Recently, adsorption has gained a great attention from
researchers due to availability of the materials and associated capacity compared to conventional methods of
water treatment. Various chemical treatment methods have been employed to boost the capacity of the
adsorbents, one of them being the use of ethylenediamine. In this study, a novel quaternised adsorbent was
synthesized for complexation of Cu2+, Cd2+ and Pb2+ ions from aqueous solution. Raw Artocarpus heterophyllus
L. seeds were chemically modified with thionyl chloride followed by ethylenediamine. Both raw and quaternised
adsorbents were characterized by FTIR and applied for equilibrium complexation batch experiments. Effect of
pH, contact time, agitation speed, adsorbent dosage and initial concentration were investigated. FTIR results
showed that amino groups were successfully anchored into the quaternised adsorbent and this increased its
complexation capacity. Batch results indicated that complexation of the three metal ions was at optimal at pH
values between 4.2 and 6.4. Contact time of 20 minutes and 15 minutes for raw and quaternised adsorbents
respectively. Agitation speed of between 150 rpm and 175 rpm. Raw and quaternised dosage of 15 mg and 10
mg; 13 mg and 10 mg; 15 mg for Cu2+, Cd2+ and Pb2+ ions respectively and optimal concentration of 30 ppm.
Equilibrium experimental data fitted well in Langmuir isotherm with adsorption capacities of 21.3220 mg g
-1
,
19.6850 mg g
-1
and 21.8818 mg g
-1
for raw and 33.7838 mg g
-1
, 25.1256 mg g
-1
and 34.0136 mg g
-1
for
quaternised adsorbent for Cu2+, Cd2+ and Pb2+ions respectively implying a chemisorption mechanism. The
results confirmed potentiality of Artocarpus heterophyllus L. seeds for heavy metal ions removal from aqueous
solutions