Synthesis and surfactant modification of clinoptilolite and montmorillonite for the removal of nitrate and preparation of slow release nitrogen fertilizer

• Published in: Journal of hazardous materials 2012-08, Vol.227-228, p.292-300
• Main Authors: Bhardwaj, Deepesh, Sharma, Monika, Sharma, Pankaj, Tomar, Radha
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Bentonite - chemistry; bromine; Cetrimonium Compounds - chemistry; Clinoptilolite; Fertilizer; Fertilizers; Isotherms; leaching; Montmorillonite; Nitrate; Nitrates; Nitrates - chemistry; Nitrogen; nitrogen fertilizers; Nutrients; Quaternary Ammonium Compounds - chemistry; silicates; soil; sorption isotherms; Surface-Active Agents - chemistry; Surfactant; Surfactants; Synthesis; Zeolites - chemistry
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2012.05.058

[Display omitted] ► Clinoptilolite and montmorillonite have been synthesized hydrothermally. ► SMCHDTMAB appears to be better adsorbent. ► Surfactant modification increases the adsorption capacity of silicates to retain nitrate. ► The maximum monolayer capacity for nitrate at 303K was 125.0mgg−1. ► The adsorption data fitted well with the Langmuir and Freundlich isotherms. This article introduces the synthesis of clinoptilolite and montmorillonite, and their surfactant modification by using solutions of hexadecyltrimethylammonium bromide (CH3(CH2)15N(Br)(CH3)3, HDTMAB) and dioctadecyldimethylammonium bromide ((CH3(CH2)17)2N(Br)(CH3)2, DODMAB). The feasibility of using surfactant modified silicates (SMSs) as a potential adsorbent for nitrate and for slow release of nutrient has been investigated. Adsorption isotherms of NO3− on SMSs have been measured at aqueous concentration of 160–280mgL−1. The SMSs show much higher adsorption capacity than the unmodified materials as determined by Langmuir adsorption isotherm. The surfactant modification and increased surfactant loading concentration enhance the nitrate anion retaining capacity of silicates (montmorillonite (16.05mgg−1)