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A Raoult's law-based method for determining the number average molecular weight of coal tars is presented. The method requires data from two-phase coal tar/water equilibrium experiments, which readily are performed in environmental laboratories. An advantage of this method for environmental samples is that it is not impacted by the small amount of inert debris often present in coal tar samples obtained from contaminated sites. Results are presented for 10 coal tars from nine former manufactured gas plants located in the eastern United States. Vapor pressure osmometry (VPO) analysis provided similar average molecular weights to those determined with the Raoult's law-based method, except for one highly viscous coal tar sample. Use of the VPO-based average molecular weight for this coal tar resulted in underprediction of the coal tar constituents' aqueous concentrations. Additionally, one other coal tar was not completely soluble in solvents used for VPO analysis. The results indicate that the Raoult's law-based method is able to provide an average molecular weight that is consistent with the intended application of the data (e.g., modeling the dissolution of coal tar constituents into surrounding waters), and this method can be applied to coal tars that may be incompatible with other commonly used methods for determining average molecular weight, such as vapor pressure osmometry.

With an increase in demand of freshwater and depleting water sources, it is imperative to switch to seawater as a regular source of water supply. However, due to the high total dissolved solid content, it has to be desalinated to make it drinkable. While desalination technologies have been used for many years, mass deployment of such technologies poses a number of challenges like high energy requirements as well as high negative environmental impact through side products and CO2 emissions. The purpose of this paper is to present a sustainable technology for desalination. Forward osmosis, an emerging technology, is compared with the other commonly used technologies worldwide, namely, multieffect distillation, multistage flash distillation, and reverse osmosis as well as other emerging technologies like vapour compression, solar humidification dehumidification, nanofiltration, and freezing desalination. As energy consumption and associated greenhouse gas emissions are one of the major concerns of desalination, this paper concludes that forward osmosis is an emerging sustainable technology for seawater desalination. This paper then presents the challenges involved in the application of forward osmosis in India and presents a plant setup. In the end, the cost comparison of a forward osmosis and reverse osmosis plant has been done and it was concluded that forward osmosis is economically better as well.

E-commerce packaging waste is a matter of concern, especially with the increasing popularity of online shopping due to the COVID-19 pandemic. This leads to the generation of a massive amount of e-commerce packaging waste as well as resource utilisation and CO 2 emissions that go into the production of packaging. The aim of this study is to analyse the impact of COVID-19 on consumer trends in the e-commerce industry, quantitatively analyse the carbon emissions of packaging used, and present a circular model to reduce the demand for virgin packaging. Using a convenience sampling method, an online questionnaire was administered to 285 respondents to gather data on changes in shopping practices due to the COVID-19 pandemic, consumer awareness levels and observations on packaging materials, and practices employed by e-commerce companies. It was found that the number of orders placed per month increased after the onset of the pandemic and that most households dispose of packaging with household wastes as opposed to reusing or recycling. Primary data (study participants packaging waste production) in combination with secondary data (emission factors) was further used to calculate emissions due to mixed packaging waste, which came out to be 2,705.94 kg CO 2 e per metric tonne of waste produced. In addition, the paper presents a practical solution to reducing virgin packaging material production, as well as modifications in packaging used to ensure efficient working of the packaging reuse model when implemented by the e-commerce companies.

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