Coconut tree sawdust was collected from a saw mill.
The waste sawdust was dried in sunlight and used for the
carbon preparation. The dried sawdust was sieved using
a 2-mm sieve. Then it was subjected to carbonisation at
700°C for 30 min using a digital mue furnace: 25 g of
sawdust was taken in a 100 ml capacity silica crucible
and kept in the mue furnace, for attaining a temperature
of 700°C, for about 30 min. After 30 min the
carbonised material was taken out and immediately
covered with a petridish to avoid contact with atmospheric
air. This carbon was used for further treatment
studies. Six samples of dyeing industry wastewater were
collected in plastic cans, which were already washed and
rinsed with distilled water, from a dyeing industry at
Tirpur. A typical treatment consisted of agitating 0.5 g
of adsorbent and 100 ml of wastewater in 300 ml bottles
at 120 rpm using a mechanical shaker These bottles
were withdrawn from the shaker at predetermined times.
The sample was separated by centrifugation at 1000 rpm
and the supernatant was analysed using an UV-spectrophotometer
(U-3210, Hitachi, Japan). The adsorbent
dose was varied from 0.5 to 3.5 g per 100 ml wastewaters
and the pH from 1 to 9 using HCl or NaOH. The
analysis of wastewater was carried out using standard
methods (APHA, 1980). Experiments were carried out
in duplicate and the maximum deviation was 3%.