Name: LARISSA LOPES ROLDI
Publication date: 16/08/2018
Advisor:
Name |
Role |
|---|---|
| EDUMAR RAMOS CABRAL COELHO | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| EDUMAR RAMOS CABRAL COELHO | Advisor * |
| MIGUEL ÂNGELO SCHETTINO JUNIOR | External Examiner * |
| RENATO RIBEIRO SIMAN | Internal Examiner * |
Summary: Contamination of water resources for human supplying by micro pollutants is a difficulty
that conventional water treatments do not solve effectively. 2,4-Dichlorophenoxyacetic
acid (2,4-D) is a micro-contaminant fouling pesticide that has high toxicity to the aquatic
ecosystem and to humans, requiring its removal from this environment. The most
widely used method for the removal of these compounds is adsorption on activated
carbon, WHERE the substance interacts with clusters present on the coal surface, so
that, after filtration, the compound is removed. In the attempt to develop new materials
for the adsorption of 2,4-D, Coffee grounds (CG) and Coffee husks (CH), in natura and
carbonized, were used in adsorption studies, as they are highly available materials in
Brazil and have lower cost of obtaining when compared to activated charcoal. This
study evaluated the surface characteristics of these materials by Analysis of Specific
Surface Area (BET), Scanning Electron Microscopy (SEM), Thermogravimetry (TG)
and Point Zero Charge (PZC). Studies were carried out to set equilibrium time and the
adsorbent mass to be used, but it was not possible to determine any adsorption of 2,4-
D using CG and CH in natura. Thus, adsorption studies varying the initial 2,4-D
concentration and the pH of the solution were conducted only for activated carbon AC
and carbonized CG and CH. To the isotherms, generated from the adsorption study,
the Langmuir and Freundlich models were applied to obtain parameters of the
adsorption process. In general, carbonized CG presented higher adsorption in relation
to carbonized CH, presenting qA MÁX values of 23.4 and 4.4 mg/g, respectively.
However, both had lower performance than AC (qA MÁX = 94.0 mg/g). Among the
studied pH, it was observed that in acid pH's, 2,4-D removal was higher for all studied
adsorbents.
