In this chapter, we have reviewed the results of different studies on the removal
of aquatic pollutants especially heavy metals and organics by various biosorbents. Among
several sorbents used by different researchers, only agricultural solid wastes without any
chemical treatments, i.e. identified as “low cost adsorbents”, are considered. In the
adsorption process, the effect of different parameters such as: pH, dose of adsorbent, initial
pollutant concentration, contact time, adsorbent particle size, temperature, etc. have been
investigated. Among them, pH was found to play an important role in the removal of
pollutants by biosorbents. The optimum value of pH for maximum adsorption is reported
based on the results of various studies. In some cases, the best adsorption isotherms and
kinetic models are also introduced for the prediction of adsorbent behavior. This summary
information would help in selecting and deciding suitable cheap biosorbents based on local
agricultural wastes for the removal of common pollutants globally.
Keywords: Water treatment, Agricultural wastes, Biosorbents, Heavy metals,
Organic pollutants, Dyestuff, Phenolic compounds, Pesticides, Functional groups,
Adsorption, Isotherms, Kinetics, Adsorbate, Capacity, Adsorption mechanism,
Langmuir isotherm, Freundlich isotherm, External mass transfer, Intraparticle
diffusion, pH effect.
