Sorption of Heavy Metal Ions (Cu2+ and Cd2+) From Simulated and Industrial Wastewaters Using Sugarcane Biomass

Abstract

The widespread use of heavy metals in different manufacturing processes has resulted in their presence in the air, soil and aquatic ecosystems. Many manufacturing processes release their effluents into nearby streams and rivers due to non-availability of waste treatment technologies in the developing world. Industrialization has therefore been reported to be a major anthropogenic source of these elements and their compounds waterbodies. Conventional methods that are currently being used in the developed world (such as chemical precipitation, ultra-filtration, reverse osmosis, etc) are expensive and so, unaffordable to small-scale businesses prevalent in developing economies. The need for alternative, cheaper and available technologies therefore, cannot be over-emphasized. This study attempted to remove heavy metals (Cu²⁺ and Cd²⁺) from simulated and industrial (paint and textile) wastewaters using sugarcane biomass. A synthetic resin (Chelex) was used as control. Batch sorption experiments were conducted to assess the influence of contact time, adsorbent dose, adsorbate concentration, pH, agitation speed, temperature and particle size. Increases in the parameters (except particle size) gave corresponding increases in percentage adsorption of both metals. Optimal temperature for adsorption was achieved at 50oC above which adsorption declined considerably. Experimental data for Cu²⁺ and Cd²⁺ fitted well into freundlich and langmuir isotherms. In textile effluent, 100% adsorption was achieved for both metals using sugarcane biomass in contrast to 89% and 91% for Cu²⁺ and Cd²⁺ respectively in chelex, a synthetic resin. Similarly, adsorption was 100% for both metals using the biosorbent. Sugarcane biomass may therefore be utilized for water and wastewater remediation in the developing world. Its biodegradability gives comparative advantage over alternative synthetic and expensive resins since its disposal will be more environmentally friendly.