In the heart of Nigeria, researchers are turning a humble coconut shell into a powerful tool for cleaning up laboratory wastewaters, offering a promising solution for the energy sector’s growing environmental challenges. Abdulhalim Musa Abubakar, a chemical engineering professor at Modibbo Adama University and the University of Maiduguri, has led a study that transforms coconut shells into activated carbon, a low-cost adsorbent that effectively removes methylene blue (MB) dye from laboratory effluents. The research, published in the journal ‘Measurement: Energy’ (translated as ‘Measurement: Energy’), not only addresses a pressing environmental issue but also opens doors to more sustainable and cost-effective wastewater treatment methods.
Laboratory effluents containing dyes like MB pose significant risks to human health and the environment. Current treatment methods can be expensive and energy-intensive. Abubakar’s team turned to coconut shells, an abundant and inexpensive agricultural waste product, to create an activated carbon adsorbent. “We wanted to find a low-cost, locally available material that could effectively remove dyes from wastewater,” Abubakar explains. “Coconut shells are readily available in Nigeria and many other tropical regions, making them an ideal choice for this application.”
The researchers activated the coconut shells using sodium hydroxide, converting them into a highly porous activated carbon. Through a series of optimization studies, they determined the ideal conditions for adsorbing MB from wastewater. The process involves a delicate balance of factors such as the amount of activated carbon used, the pH level, temperature, contact time, and initial dye concentration. The team found that using 0.2 grams of coconut shell-activated carbon (CS-AC) at a pH of 6, a temperature of 303K, and a contact time of 45 minutes achieved the best results. Under these conditions, the maximum adsorption capacity was 153.765 milligrams per gram, with a removal efficiency of 62.285%.
To understand the adsorption process better, the researchers applied various isotherm and kinetic models. The Langmuir model, which assumes a monolayer adsorption process, provided the best fit using nonlinear regression techniques. This model suggested a high maximum capacity of 172.12 milligrams per gram, indicating favorable monolayer adsorption. The Freundlich model, which describes heterogeneous adsorption, also yielded realistic results, with an adsorption intensity of 2.7 and a capacity factor of 56.48 liters per gram.
The study also revealed that the adsorption process is predominantly physical, involving weak van der Waals forces, and heterogeneous, occurring on a surface with different types of sites. “The adsorption behavior of CS-AC towards MB is complex, but our findings suggest that it is a favorable, heterogeneous process,” Abubakar notes. “This is crucial for developing more efficient and cost-effective wastewater treatment methods.”
The implications of this research extend beyond laboratory wastewater treatment. The energy sector, which often deals with dye-contaminated wastewater from various processes, could benefit significantly from this low-cost and energy-efficient solution. “The potential applications of CS-AC are vast,” Abubakar says. “It could be used in various industries, from textiles to energy production, to treat wastewater and reduce environmental pollution.”
The study also highlights the importance of using nonlinear regression techniques for modeling adsorption processes. The researchers found that nonlinear regression techniques provided more reliable estimates than traditional graphical methods. This insight could lead to more accurate and efficient modeling of adsorption processes in the future.
As the world grapples with the challenges of environmental pollution and climate change, innovative solutions like CS-AC offer a glimmer of hope. Abubakar’s research not only addresses a pressing environmental issue but also paves the way for more sustainable and cost-effective wastewater treatment methods. “Our goal is to develop technologies that are not only effective but also accessible and affordable,” Abubakar concludes. “By turning agricultural waste into a valuable resource, we can create a more sustainable future for all.”
The research published in ‘Measurement: Energy’ (translated as ‘Measurement: Energy’) serves as a testament to the power of innovation and the potential of low-cost, locally available materials to address global environmental challenges. As the energy sector continues to evolve, solutions like CS-AC will play a crucial role in shaping a more sustainable and environmentally friendly future.