Volatilization of Standalone Dicamba and Dicamba Plus Glyphosate as Function of Volatility Reducer and Different Surfaces

Dicamba is a herbicide with a moderate volatility profile. Such volatility behavior can be significantly diminished with formulation technology and volatilization reducers. The objective of this study was to quantify the volatility potential of dicamba diglycolamine salt (DGA) in a standalone application or in tank mixture with glyphosate (potassium salt) (GK), with and without volatilization reducer (acetic acid—VaporGrip®) from different surfaces. The combination of these products was applied on four different surfaces (glass slides, corn straw, and dry and moist sandy soil) with three replications, and the experiment was duplicated. The application was performed indoors with an automated sprayer. After application, targets were positioned in cartridges containing two filters in series. Cartridges were placed in a vapor collection system that consisted of a chromatographic oven with constant temperature of 40 °C attached to a vacuum pump for 24 h. After this period, liquid samples were obtained from an extraction procedure of filters and surfaces, which corresponded to the volatilized and deposited portions of the herbicides, respectively. The samples were analyzed by liquid chromatography–tandem mass spectrometry (LC-MS/MS). The use of this method provided a rapid and consistent evaluation, in which the treated surface exerts a direct influence on the amount of volatilized dicamba. The mixture of dicamba and glyphosate solutions exhibited different volatility profiles as a function of the treated surfaces. The DGA applied alone had the largest level of volatility when applied on moist soil and the lowest level of volatility in dry soil and straw. The DGA with GK had volatilities similar in dry soil, wet soil and straw. The volatility reducer in the tank mixture was effective in reducing DGA dicamba volatilization, regardless of the sprayed surface and the tank mixture, making the application of dicamba safer from the volatilization standpoint.

Principles and advancements of air gap membrane distillation

In recent years, membrane distillation (MD) has evidently emerged as one of the promising separation processes, with increasing areas of application including but not limited to desalination, pharmaceutical and textile wastewater purification, food processing, concentration of aqueous solution, breaking azeotropic mixtures, and extraction of volatile organic compounds. Primarily, MD has been categorized on the basis of vapor collection and condensation arrangement methods. Among the various categories, air gap membrane distillation (AGMD), in which an air gap is maintained across the membrane and the cooling plate, turns out to be an important and efficient process. Lately, AGMD has received significant attention of researchers around the world which motivates the present work. This paper aims to review the work done so far concerning the AGMD in order to provide a holistic view that covers the principles and applications of AGMD, effect of process parameters, membrane parameters, mathematical modeling, fouling, temperature and concentration polarization, types of membrane module, energy consumption, recent developments in AGMD process, cost estimation, and heat integration with AGMD. To the best of our knowledge, the present work is the first attempt to exhaustively review the AGMD process.

Chemoselective Polymers, Nanoparticles, and Nanotubes in Chemical Sensor and Preconcentrator Applications

The functionalization of polymers and nano-materials with 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) groups provides materials suitable for a variety of preconcentrator and sensor applications. These are especially useful in high vapor pressure, hydrogen-bond basic vapor collection. These specific interactions lead to high efficiency collection of basic analytes such as DMMP (organophosphonates), DNT, and TNT (nitroaromatics). The lower vapor pressure analytes such as RDX have a larger dependence on surface interactions without specific (hydrogen bond) interactions. The use of carbosilane polymers with HFIP pendant groups offers dramatic improvements over fluoropolyol (FPOL) and siloxane polymers in sensor and precon applications. The sorbent capacity and thermal stability are both dramatically improved. In this work we will demonstrate the use of Carbon Nanotube (CNT) composites with HFIP polymers as sorbent coatings and evaluate their use as SPME coatings.

Vapor Recovery on Tankers from Design to Operation

Vapor control legislation has presented the vessel operator with a multitude of factors that must be given consideration during the retrofitting of a vessel vapor control system. This paper discusses notable aspects concerning the integration of various facets of vapor control as they relate to vessel installations from conceptual design through operation. While complete vessel collection and processing systems are permitted by the Regulations, discussions in this paper are limited to vessel collection systems because, for the most part, industry has adopted the concept of limiting vessels to the collection of vapors only, with subsequent transfer to shoreside facilities for processing. Discussions are based on experience gained during development of vapor collection systems for two different classes of inerted, multi-grade cargo product tankers. Accordingly, some topics are not applicable or can be simplified when considering installations on board tank vessels carrying single cargoes or on non-inerted tank vessels.