Bactericidal activity and silver release of porous ceramic candle filter prepared by sintering silica with silver nanoparticles/zeolite for water disinfection

Abstract

Porous ceramic candle filters (PCCF) were prepared by sintering silica from rice husk with silver nanoparticles (AgNPs)/zeolite A at about 1050 °C to create bactericidal PCCF/AgNPs for water disinfection. The silver content in PCCF/AgNPs was of 300-350 mg kg −1 determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and the average pore size of PCCF/AgNPs was of 50-70 Å measured by Brunauer-Emmett-Teller (BET) method. The bactericidal activity and silver release of PCCF/AgNPs have been investigated by flow test with water flow rate of 5 L h −1 and initial inoculation of E. coli in inlet water of 10 6 CFU/100 mL. The volume of filtrated water was collected up to 500 L. Results showed that the contamination of E. coli in filtrated water was <1 CFU/100 mL and the content of silver released from PCCF/AgNPs into filtrated water was <1 μg L −1 , it is low, far under the WHO guideline of 100 μg L −1 at maximum for drinking water. Based on the content of silver in PCCF/AgNPs and in filtrated water, it was estimated that one PCCF/AgNPs could be used to filtrate of ∼100 m 3 water. Thus, as-prepared PCCF/AgNPs releases low content of silver into water and shows effectively bactericidal activity that is promising to apply as point-of-use water treatment technology for drinking water disinfection.

EFFECT OF NANOSILICA FROM RICE HUSK ON THE GROWTH ENHANCEMENT OF CHILI PLANT (Capsicum frutescens L.)

“…Silica and nanosilica from rice husk have been applied in various fields such as adsorbents, carriers, fillers, blending in Portland cement, zeolite production, drug delivery system, etc [3 -5]. Recently, silica (SiO 2 ) and nanosilica from rice husk (RH) have been also applied for production of porous ceramic for water treatment [6], and for plant growth promotion and elicitation [2,7,8]. RH is an agro-waste product, and about 600 million tons are generated each year around the world [9].…”

Design and development of nanoceramic filter as point of use water filter

“…Shameli et al synthesised silver nanoparticle and confirmed it by using absorption wavelength at 394-401 nm in UV-Visible spectroscopy [9]. Similarly, Nguyen et al synthesised silver nanoparticle and also had the maximum absorption wavelength at 427 nm [10].…”

Mechanisms and efficacy of disinfection in ceramic water filters: A critical review

“…pH ¼ 9) (Bielefeldt et al, 2013;Mittelman et al, 2015). An alternative perspective however is that a step-wise reaction occurs, as shown in Reaction 8, whereby silver solid particles bond with oxygen in the water or on the ceramic surface, forming AgO or Ag 2 O, which subsequently reacts with hydrogen and dissociates into dissolved silver ions and water (Bielefeldt et al, 2013;Fauss et al, 2014;Hong et al, 1995;Liu & Hurt, 2010;Nguyen, 2014). Consequently, Mittelman et al (2015), reported silver release to decrease from 0.6 mg/L to 0.1 mg/L and then 0.008 mg/L as pH increased from 5 to 7 to 9 sequentially (Mittelman et al, 2015), demonstrating a clear relationship.…”