Application of central composite design for optimization of the removal of humic substances using coconut copra

Terri Zhuan Ean Lee,Sila Kittiwachana,Nurul Aida Lu Mohd Irwn Lu,Chanida Krongchai,Siong Fong Sim

doi:10.1007/s40090-015-0041-0

Terri Zhuan Ean Lee, Sila Kittiwachana + Show 3 more

Open Access

https://doi.org/10.1007/s40090-015-0041-0

Copy DOI

Abstract

Coconut copra is a potential biosorbent for removal of humic substances from peat swamp runoff. In this paper, response surface methodology was applied to evaluate the optimum conditions for removal of humic substances from peat swamp runoff using modified coconut copra. Batch adsorption experiments were conducted according to central composite design. Results show that the quadratic model is best fitted for predicting the removal efficiency with regression coefficients closer to 1 and a lower root mean square error. Dosage is found to have significant influence on the removal efficiency with p < 0.05. Response surface models further identified the optimum dosage, contact time and temperature at 4.56 g modified coconut copra per 100 mL peat swamp runoff, 42.9 min and 56.8 °C/329°K, respectively attaining the maximum removal efficiency of 88.19 %. The predicted removal efficiency was confirmed experimentally under the modelled optimum conditions; the removal efficiency attained (86.54 %) was in good agreement with the predicted value.

Highlights

Humic substances are the products of biological and chemical decomposition of living organisms
Note that this paper focuses on examining the optimum conditions for removal of humic substances when multiple variables are considered simultaneously; the information derived is important for scaling up operation
Coconut copra is a potential biosorbent for water and wastewater treatment

Summary

Introduction

Humic substances are the products of biological and chemical decomposition of living organisms. The presence of humic substances in water can have a significant impact on the treatability of the water and the efficiency of chemical disinfection process They are believed to be the precursors to the formation of carcinogenic disinfection by-products. In the conventional water treatment system, humic substances are removed using the coagulation and flocculation approach [2,3,4] requiring excess amount of coagulant and are generally limited by high operational and material costs. Other adsorbents such as activated carbon, zeolite, and mesoporous silica have been employed for isolation of humic substances but these adsorbents are very expensive.

Methods

Results

Conclusion