Experimental investigation on the effects of clay colloid-facilitated ammonium transport through saturated porous media under variable transport conditions

Ammonium contamination is one of the major environmental issues in subsurface contamination and groundwater which in turn poses risks to human health. Predicting and formulating desirable situations is necessary for the study of NH4+ ion adsorption and transport in the environment. The purpose of the present paper is to assess the influence of various factors, such as different colloidal concentration, different size of porous media and different flow rates on colloid-facilitated NH4+ ion transport. In order to understand the influence of colloid concentration on NH4+ ion transport in porous media, few soil column experiments were performed in laboratory scale. Different clay colloidal concentrations with NH4+ ion solution as contaminant were supplied to the soil column and the leached out solution was tested using UV-vis spectrophotometer to find the concentration of NH4+ ion; 500ppm clay colloidal concentration in fine sand medium at 5ml/min flow rate has been identified as most suitable condition for NH4+ ion subsurface adsorption with highest cumulative NH4+ ion adsorption of 1.9mg/g, whereas 200ppm clay colloidal solution had least cumulative NH4+ ion adsorbed values than other solutions. TherefoZhangre, 200ppm colloid solution was found to be most efficient for NH4+ ion transport. The efficiency of NH4+ ions transport in all the solutions in the study was doubled at a flow rate of 15ml/min than at 5ml/min. The outflow NH4+ ion concentration was lower for fine sand than medium sand in all the cases in the study. The results illustrated that variable factors in the study can either facilitate or retard ammonium ion adsorption.

Automated summary

The study evaluated the influence of different factors on colloid-facilitated NH4+ ion transport, finding that 500ppm clay colloid concentration and 5ml/min flow rate were the optimal conditions for NH4+ ion subsurface adsorption, while 200ppm colloid solution was the most efficient for NH4+ ion transport. The efficiency of NH4+ ions transport in all solutions doubled at a flow rate of 15ml/min compared to 5ml/min.