Extração de biopolímero de pinhas de Pinus elliottii Engelm para aplicação como coagulante no processo de tratamento de água

Abstract

Water is the vital element for human existence, and it is treatment prevents waterborne diseases from reaching the population. By replacing the chemical inputs used in conventional treatment with biodegradable materials, there is a decrease in toxic by-products and process residues. Thus, one of the alternatives for water treatment may be the use of natural biopolymers. Pine in Brazil is grown for timber extraction, and the pine cone ends up being discarded. Thus, the objective of the present study was to reuse this discarded material, extracting the biopolymers, and using them as coagulants in the water treatment. The initial results indicate that the coagulant dosage range defined between 10 and 100 mg L-1 and pH from 3.0 to 12.0 resulted in an increase in apparent color and turbidity parameters, and that only lower dosages showed considerable efficiency. For the dosage range between 1.7 and 5.0 mg L-1, apparent color removal was observed above 95 % at basic pHs with dosages of 3.4 and 5.0 mg L-1, at 40 minutes sedimentation. In these same conditions, after 1200 minutes, 100 % of apparent color removal was achieved. Turbidity at 40 minutes reached 82 % removal (dosage of 1.7 mg L-1 and pH 12.0). In the longest sedimentation time, this parameter was completely removed. The absorbance at 254 nm reached 82% removal at 40 minutes and 87 % at 1200 minutes. Supported by this, optimal values of coagulant dosage of 1.0 mg L-1 and pH of 12.55 were indicated for the 40 minutes of sedimentation, and 5.7 mg L-1 and pH of 12.55 for the 1200 minutes, resulting in the latter, as the most efficient in removing apparent color, turbidity and absorbance from treated water. However, considering implementation costs, in addition to efficiency, the coagulant dosage of 1.0 mg L-1 and pH of 12.55 was indicated as adequate under the operating conditions used. Therefore, Pinus elliottii pine cone biopolymers can be used as a natural and sustainable source for water treatment.