The application of low-cost adsorbents obtained from plant wastes as a replacement for costly conventional methods of removing
heavy metal ions from wastewater has been reviewed. It is well known that cellulosic waste materials can be obtained and employed
as cheap adsorbents and their performance to remove heavy metal ions can be affected upon chemical treatment. In general, chemically
anhydride
modified sugarcane bagasse for treatment of Cu,
Cd and Pb from aqueous solutions. Sugarcane bagasse
consists of cellulose (50%), polyoses (27%) and lignin
(23%). The presence of these three biological polymers
causes sugarcane bagasse rich in hydroxyl and phenolic
groups and these groups can be modified chemically to produce
adsorbent materials with new properties. The authors
reported that the hydroxyl groups in sugarcane bagasse
could be converted to carboxylic groups by using succinic
anhydride. The carboxylic groups were later reacted with
three different chemicals mainly NaHCO3, ethylenediamine
and triethylenetetramine to produce new properties of
adsorbent materials which showed different adsorption
capacities for metal ions. It was found that sugarcane
bagasse treated with ethylenediamine and triethylenetetramine
shows a remarkable increase in nitrogen content compared
to untreated sample, and triethylenetetramine
modified sugarcane bagasse has a higher increasing extent.
The presence of amide group was also detected in ethylenediamine
and triethylenetetramine modified sugarcane bagasses
as a result of the reaction between –COOH and –
NH2 groups. Kinetic studies showed that equilibrium time
for adsorption of Cu, Cd and Pb onto tethylenediamine
and triethylenetetramine modified sugarcane bagasses were
slower than that for adsorbent modified with NaHCO3.
Triethylenetetramine modified sugarcane bagasse was the
best adsorbent material for removal of Cd and Pb since
the adsorption capacities for both metals are two times
higher than unmodified sugarcane bagasse. This was probably
caused by the higher number of nucleophilic sites
introduced in triethylenetetramine modified sugarcane
bagasse. When sugarcane bagasse was modified with methanol,
however, the resulting adsorbent did not show a good
uptake of cadmium as the maximum adsorption capacity
was 6.79
The application of low-cost adsorbents obtained from plant wastes as a replacement for costly conventional methods of removing
heavy metal ions from wastewater has been reviewed. It is well known that cellulosic waste materials can be obtained and employed
as cheap adsorbents and their performance to remove heavy metal ions can be affected upon chemical treatment. In general, chemically
anhydride
modified sugarcane bagasse for treatment of Cu,
Cd and Pb from aqueous solutions. Sugarcane bagasse
consists of cellulose (50%), polyoses (27%) and lignin
(23%). The presence of these three biological polymers
causes sugarcane bagasse rich in hydroxyl and phenolic
groups and these groups can be modified chemically to produce
adsorbent materials with new properties. The authors
reported that the hydroxyl groups in sugarcane bagasse
could be converted to carboxylic groups by using succinic
anhydride. The carboxylic groups were later reacted with
three different chemicals mainly NaHCO3, ethylenediamine
and triethylenetetramine to produce new properties of
adsorbent materials which showed different adsorption
capacities for metal ions. It was found that sugarcane
bagasse treated with ethylenediamine and triethylenetetramine
shows a remarkable increase in nitrogen content compared
to untreated sample, and triethylenetetramine
modified sugarcane bagasse has a higher increasing extent.
The presence of amide group was also detected in ethylenediamine
and triethylenetetramine modified sugarcane bagasses
as a result of the reaction between –COOH and –
NH2 groups. Kinetic studies showed that equilibrium time
for adsorption of Cu, Cd and Pb onto tethylenediamine
and triethylenetetramine modified sugarcane bagasses were
slower than that for adsorbent modified with NaHCO3.
Triethylenetetramine modified sugarcane bagasse was the
best adsorbent material for removal of Cd and Pb since
the adsorption capacities for both metals are two times
higher than unmodified sugarcane bagasse. This was probably
caused by the higher number of nucleophilic sites
introduced in triethylenetetramine modified sugarcane
bagasse. When sugarcane bagasse was modified with methanol,
however, the resulting adsorbent did not show a good
uptake of cadmium as the maximum adsorption capacity
was 6.79
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