Page 11 - KVIS Book

ENS02A, ENS05I

Absorption of Waste Phosphate using Biochar and Chitosan
gel beds for Portulaca grandiflora growth

Natnicha Techaamnuayporn, Puttaranun Boonchit, Thanawut
Wilairatanadilok
Kamnoetvidya Science Academy, Thailand
Supervisor: Arjaree Thirach
Email: thanawut_w@kvis.ac.th

Nowadays, many people unintentionally pollute the water resources by releasing
detergent and substances into the water. This project was conducted to reduce the
concentration of phosphate ions in water by developing biochar and chitosan gel beds
for phosphate absorption. The most efficient ratio between biochar and chitosan was
determined, and mixed in different types of gel include pectin, agar and polyvinyl
alcohol; then after absorbing phosphate ions in the water, these gel beds were used
for planting Portulaca grandiflora. From spectrophotometry analysis, the result
showed that the most suitable ratio between biochar and chitosan was 3:18 by weight,
absorbing phosphate ions at 24.62 mgP/L from an initial concentration at 50 mgP/L.
After absorption of phosphate, the gel beds were used for planting Portulaca
grandiflora, which was observed for growth for 2 weeks. Only the gel beds produced
form agar were found to be suitable for planting. After 10 days, new sprouts were
found on the controlled soil set and gel beds with biochar and chitosan. In contrast, the
set of agar gel without biochar and chitosan showed no change. However, other
measurable criteria of the new sprouts could not be determined since the plants were
eaten by insects and snail. In conclusion, using the proper ratio of biochar and chitosan
with agar gel can produce the gel beds suitable for absorbing phosphate from
wastewater, which can be subsequently used for small plant cultivation.

Keywords: Phosphate absorption, Biochar, Chitosan, Gel beds, Portulaca grandiflora