Abstract
M.Tech. (Biotechnology)
Due to industrialization and development, the environment is under severe stress as a result of pollution. Water bodies are being compromised due to inadequate remediation technologies available. Conventional technologies are known to cause secondary pollution upon usage, which is of serious concern as they do not eliminate the predicament. Non-conventional methods are being considered because they are environmentally friendly and cost efficient. Dyes are one of the primary pollutants of water resources being very toxic and when discharged into the environment, they pose a threat to human and animal health due to their tetragenic, mutagenic and carcinogenic potentials.
This study explores the use of microorganisms in bioremediation of dyes. In doing so, four bacteria viz: Gram-negative (i.e., E. coli, and Pseudomonas aeruginosa) and Gram-positive (i.e.,Bacillus subtilis, and Bacillaceae bacterium) were used. The bacteria were subjected to physical pre-treatment using an autoclave, mechanical pretreatment by grinding the inactive biomass and lastly, chemical pre-treatment using chemicals such as nitric acid, propyl amine, calcium chloride and ammonia. The pre-treatment techniques were applied to investigate their effect on the adsorption of dye.
The Lagergren pseudo second-order kinetic was used to deduce the adsorption capacities as it was the best fit, implying that adsorption occurred by the chermisoption mechanism. The adsorption capacities of the bacteria improved tremendously from 68.49 to 161.29 mg/g in comparison to that of the untreated biomass (9.37 to 29.11 mg/g). It was also observed that in untreated biomass, no methyl orange (MO) adsorption took place whereas in treated biomass, bacteria had the ability to absorb and remove MO. The Fourier Transform Infrared (FTIR) spectra of the bacterial cell walls revealed the presence of functional groups (amines, carboxylic acids, alcohols, aldehyde and amides).Meanwhile, data obtained on the Scanning Electron Microscope (SEM) showed a homogenous surface and finer particles, which demonstrate an increase in the surface area of the treated bacterial cells. The Gram-positive and Gram-negative bacteria exhibited the ability to remove cationic and...