Vanadium removal by cationized sawdust produced through iodomethane quaternization of triethanolamine grafted raw material

Performance and Enhancement of Various Fillers Guiding Vanadium (V) Bioremediation

Bioremediation of vanadium (V) pollution in groundwater is an emerging topic. However, knowledge of V in a biogeochemical process is limited and long-term effective removal methods are lacking. V(V) remediation processes by various kinds of auxiliary fillers (maifanite-1, maifanite-2, volcanic rock, green zeolite and ceramsite), agricultural biomass and microbial enhancing were explored in this study. In tests without inocula, the V(V) removal efficiencies of ceramsite (inert filler) and maifanite-2 (active filler) were 84.9% and 60.5%, respectively. When inoculated with anaerobic sludge, 99.9% of V(V) could be removed with the synergistic performance of straw and maifanite-2. TOC (Total Organic Carbon), trace elements and three-dimensional fluorescence analyses confirmed that maifanite-2 was the most suitable among various fillers in biological V(V) removal systems with straw. This study provides a collaborative method (adsorption-biology) by using straw with maifanite-2 in V(V)-contaminated groundwater. The knowledge gained in this study will help develop permeable reactive barrier technology to repair polluted groundwater to put forward a reasonable, effective and sustainable environmental treatment strategy.

The Role of Zeolite Structure in Its β-cyclodextrin Modification and Tetracycline Adsorption from Aqueous Solution: Characteristics and Sorption Mechanism

Modification of zeolites with organic compounds is of increasing interest due to their significant potential in removing emerging pollutants from water. In this work, zeolites from fly ash with three different structure types, NaX (faujasite), NaA (Linde A) and NaP1 (gismondine), were modified with β-cyclodextrin (β-CD), and their adsorption efficacy towards tetracycline (TC) antibiotic in aqueous solutions have been studied. To assess the effect of modification on the zeolites, they were subjected to chemical, mineralogical and surface analyses using X-ray diffraction (XRD), thermogravimetry (TG), scanning electron microscope (SEM), N2 adsorption/desorption isotherm, Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The maximum adsorption capacity for NaX-CD, NaA-CD and NaP1-CD was around 48, 60, and 38 mg/g, respectively. The fastest adsorption rate was observed for NaP1-CD, which achieved adsorption equilibria after 200 min, while for NaX-CD and NaA-CD it was established after around 24 h. The kinetic data were best described by the Elovich model, followed by pseudo-second order, while the Sips and Redlich-Peterson models were the most suitable to describe the adsorption isotherms. Based on the adsorption data as well as FTIR and XPS results, TC adsorption efficacy is strongly related to the amount of CD attached to the mineral, and hydrogen bonding formation probably plays the major role between CDs and adsorbate.

Recent advances in removal techniques of vanadium from water: A comprehensive review

In recent years, with the development of economy and industry, water contaminated with heavy metal has become a global environmental problem. Vanadium (V) is an emerging contaminant reported in wastewater along with the increasing mining, smelting and recovering of vanadium ores and application in many fields as a significant national strategy resource. The increasing attention has been paid to the separations of V from water due to its potential toxic to animals and human beings. In the present study, the most common V removal techniques including adsorption, microbiological treatment, chemical precipitation, solvent extraction, electrokinetic remediation, photocatalysis, coagulation and membrane filtration are presented with discussion of their advantages, limitations and the recent achievements. Several major influencing factors and mechanisms of various processes have been briefly analyzed. Some research perspectives are proposed for improving the capacities to remove V from water. The core objective of this review is to provide comprehensive information or database for the superior approach for V removal.