Cellulose in natural flocculant applications: A review

Abstract

Natural polymeric flocculants have gained popularity in water and wastewater treatment in recent years due to their non-toxicity and biodegradability. Because of its broad availability, renewability, sustainability, and surface modification potential, cellulose is regarded as one of the foundation polymers for flocculant production and modification. The following literature review includes of an overview of coagulation-flocculation, which is the process mechanism consisting of colloid destabilization for coagulation, followed by bridging, charge neutralization, and electrostatic patch for flocculation; aspects affecting the coagulation-flocculation performance; as well as the types of coagulants and flocculants that are commonly used. Furthermore, we will go over the physical and chemical properties of flocculants, as well as their usage as a coagulant-aid in the flocculation process following coagulation and as a flocculant in direct flocculation. There is also a discussion of the most recent advances in biopolymers, which are natural materials used to alter biopolymers as flocculants such as chitosan, tannins, starch, and cellulose. Whereas there is a review of the cellulose modifications that have been performed in past research to make it a natural flocculant, the use of ramie cellulose as flocculants has never been carried out to be used as a coagulant-aid and/or flocculant in drinking water and wastewater treatment. Ramie cellulose as backbone of biomaterial composites are expected to be applied as flocculants, have good flocculation performance, and can facilitate sludge handling in water treatment plants and/or wastewater treatment plants.