A Comparative Study Of Modified And Unmodified Algae For Removal Of Lead, Cadmium And Copper From Contaminated Water

ABSTRACT

The presence of heavy metals in water due to anthropogenic and natural sources is widespread with serious effects on surface and ground water sources. There is the risk of accumulation of these metals in the body after ingestion of such waters for a long duration of time even when the concentration is low. This is because metals interfere with the functioning of body enzymes and/or bio-accumulate in hard and soft tissues in the body. There is a growing need for more clean water with the growth in population. Studies on the treatment of effluent bearing heavy metals have revealed adsorption to be a highly effective technique for the removal of heavy metals from waste water. However, most adsorbents used are expensive or require extensive processing before use. The use of inexpensive adsorbents such as algae was explored and their feasibility for the removal of heavy metals studied in detail. Many species of algae have been used to remove heavy metals in waste water. Some studies have also been done using dry algae biomass pre-treated with calcium chloride and subjected to subsequent thermal treatment to remove heavy metals in water. This is basically surface treatment of the bio-material. This study focussed on chemically anchoring a chelating agent, tetramethylethylenediamine (TMEDA) within the chemical structure of the dried bio-material to provide binding sites for metal sorption. In this study the algal material was modified by anchoring TMEDA into its chemical structure. FTIR analysis for both modified and unmodified biomaterial was carried out and confirmed the presence of functional groups capable of metal sorption. This confirmed a successfully functionalization of the algal material with TMEDA and the FTIR spectrum provided evidence of groups that act as binding sites for adsorption of metal ions. Both the modified and unmodified algal biomass were applied for removal of lead, cadmium and copper ions from wastewater. Effect of pH, contact time, sorbent dose and initial ion concentration were investigated. The data obtained was fitted into the Langmuir and Freundlich models. The adsorption kinetics was very fast as more that 90% of the metals were removed from the solution within 30 minutes. The adsorption of lead and cadmium fitted best in the Ho’s pseudo-second order kinetics confirming a multi-site interaction whereas copper followed the pseudo-first order kinetics, evidence of single site adsorption. The removal of the three metals was best at lower pH values (4.2-6.8). Beyond these values, the adsorption decreased considerably. The adsorption of copper fitted into the Langmuir adsorption isotherm with R2 values of 0.974 and 0.512 for the unmodified and modified sorbents respectively indicating a monolayer binding mechanism. Cadmium and lead fitted into the Freundlich adsorption mechanism (R2 values were: Cd modified = 0.993, unmodified=0.251, Pb modified = 0.906, unmodified = 0.929). The adsorption by the algal material did not improve upon modification since natural ligands were replaced with TMEDA which has a poor stability constant. In general the study has shown that the algal material can be used as an effective sorbent for removal of lead, cadmium and copper from contaminated waste water at low pH values.

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APA

JOHN, O (2021). A Comparative Study Of Modified And Unmodified Algae For Removal Of Lead, Cadmium And Copper From Contaminated Water. Afribary. Retrieved from https://afribary.com/works/a-comparative-study-of-modified-and-unmodified-algae-for-removal-of-lead-cadmium-and-copper-from-contaminated-water

MLA 8th

JOHN, OKAPES "A Comparative Study Of Modified And Unmodified Algae For Removal Of Lead, Cadmium And Copper From Contaminated Water" Afribary. Afribary, 26 May. 2021, https://afribary.com/works/a-comparative-study-of-modified-and-unmodified-algae-for-removal-of-lead-cadmium-and-copper-from-contaminated-water. Accessed 28 May. 2024.

MLA7

JOHN, OKAPES . "A Comparative Study Of Modified And Unmodified Algae For Removal Of Lead, Cadmium And Copper From Contaminated Water". Afribary, Afribary, 26 May. 2021. Web. 28 May. 2024. < https://afribary.com/works/a-comparative-study-of-modified-and-unmodified-algae-for-removal-of-lead-cadmium-and-copper-from-contaminated-water >.

Chicago

JOHN, OKAPES . "A Comparative Study Of Modified And Unmodified Algae For Removal Of Lead, Cadmium And Copper From Contaminated Water" Afribary (2021). Accessed May 28, 2024. https://afribary.com/works/a-comparative-study-of-modified-and-unmodified-algae-for-removal-of-lead-cadmium-and-copper-from-contaminated-water