Adsorption of ammonia from wastewater using low-cost bentonite/chitosan beads

The inexpensive and eco-friendly biosorbents bentonite-chitosan and bentonite-chitin coagulants have been successfully utilized for their ammonia removal efficiency. Bentonite was prepared using the flocculation-coagulation method. A bentonite-chitosan composite achieved its maximum ammonia removal capacity of 11.6mg/g, whereas natural bentonite and bentonite-chitin coagulants showed ammonia adsorption capacity of 0.75 and1.04mg/g, respectively. The optimum pH value was observed at pH 6, while the effect of temperature, contact time, and initial concentrations on the adsorption capacity of the adsorbent has also been investigated. Infrared spectrometry (FTIR) was used to characterize the adsorbent. Freundlich isotherm best explained the experimental data over a Langmuir model for all applied adsorbents. The ammonia adsorption followed a pseudo-second-order kinetic model. Ammonia surface adsorption followed an endothermic process, encouraged by higher temperature values.