Suthasinee Junsavang. Removal of chromium (VI) and nickel (II) in wastewater by modified fine coconut coir . Master's Degree(Technology of Environmental Management). Mahidol University. : Mahidol University, 2004.
Removal of chromium (VI) and nickel (II) in wastewater by modified fine coconut coir
Abstract:
The objective of this study is to investigate the surface areas and
functional group of fine coconut coir and the chromium and nickel removal
efficiencies in simulated solution and industrial electroplating wastewater using
nitric acid modified fine coconut coir packed in a column. The wastewater passed
through modified fine coconut coir in a bed of depth 60±0.5 cm. The effluent
samples were collected every hour for a period of 5 hours. The chromium and nickel
concentrations remaining were analyzed using Inductively Coupled Plasma (ICP).
The experiments in simulated solution were carried out at four different
pH values (2, 4, 6 and 8), at ratios of chromium to nickel (1:0 and 0:1) and three
different initial chromium and nickel concentrations (50, 75 and 100 mg/L) and at
ratio of chromium to nickel (1:1) and initial chromium and nickel concentration
(50:50 mg/L).
The results of fine coconut coir characteristic showed that the surface of
modified fine coconut coir was more porous than that of untreated fine coconut coir.
The functional group of untreated fine coconut and modified fine coconut coir
were different.
The results in simulated solution indicated that the effect of removal
depended on the pH value, eluting time and the ratio of chromium to nickel and
initial chromium and nickel concentrations. It also showed that the chromium (VI)
and nickel (II) removal efficiencies of modified fine coconut coir at different pH values
were different. As the chromium and nickel concentrations and eluting time
increased, the chromium and nickel removal efficiencies decreased. Moreover, the
presence of nickel (II) had no or very little effect on the chromium (VI) removal
efficiency and the presence of chromium (VI) had no or very little effect on the
nickel (II) removal efficiency.
The results in industrial electroplating wastewater indicated that the
pattern of the chromium (VI) and nickel (II) removal efficiencies in industrial
electroplating wastewater was similar to the chromium (VI) and nickel (II)
removal efficiencies in simulated solution. But the chromium (VI) and nickel (II)
removal efficiencies in electroplating wastewater were less than in simulated
solution. The industrial electroplating wastewater contained other ions and
impurities that could competitively bind to coconut coir