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Detection of water in organic solvents gained much importance as these solvents have been used as a medium for conducting organic reactions and water was considered as an inhibitor, when it is present in the reaction medium. There are number of methods available to measure the water content in organic solvents, however, such methods are time consuming and expensive. Here, we developed a facile method for detecting water in organic solvents using an inexpensive fluorescent probe - Rhodamine B decorated Graphene oxide (RBGO). The fluorescent probe, RBGO can be conveniently prepared by mixing the rhodamine B (RB) with graphene oxide (GO) in water. However, the probe will function as a sensor for water in the organic solvents through the release of dye upon interaction with the water present in organic solvents. Surprisingly, combination of cucurbit[7]uril (CB[7]) and RBGO increased the sensitivity of this sensor dramatically for the detection of water. This is the first example of water sensor with best detection limit by the involvement of host molecules such as CB[7]. This sensor displayed the low limit of detection (LOD) for organic solvents (LOD: 0.0015% for DMSO, 0.0025% for DMF), through the two-way process such as decomplexation and encapsulation. We presume that the role of CB [7] can be implemented in other similar sensors to enhance the sensitivity.

Good quality water is crucial to most developing nations' sustainability. However, there is a clear lack of affordable and reliable solutions to monitor water quality. According to the WHO 2022 Sustainable Development Goals report, about 3 billion people do not have information on their water quality. While off-line measurements are commonly practiced, the availability of in-situ monitoring solutions is considered critical to the generalization of water monitoring, but current technologies are bulky, expensive and usually do not target a sufficient number of quality parameters. [1]To meet this challenge, the LOTUS project (https://www.lotus-india.eu/) brings forward a low-cost, compact, versatile multiparametric chemical sensor aiming at real-time monitoring of chlorine, pH, temperature and conductivity in potable water. The proposed solution –a tube of 21.2 cm in length by 3.5 cm in diameter – is composed of a replaceable sensor head incorporating the sensing elements and a sensor body containing the acquisition and communication electronics. The sensor head integrates a 1cm² silicon chip with 2 temperature sensors (serpentine-shaped thermistors), 3 conductivity sensors (parallel electrodes in a 4-probe configuration) and a 10x2 sensor array of multi-walled carbon nanotube (CNT) chemistors. The CNT are arranged in random networks between interdigitated electrodes and are either non-functionalized or functionalized with a dedicated polymer. [1]We evaluated the performance of 7 units of this solution in Sense-city facility (located at University Gustave Eiffel, France - https://sense-city.ifsttar.fr/ ), exploiting its 44m potable water loop with 93.8-mm PVC pipes. The system was operated at 25 m3/h and 1 bar, at temperature ranging between 15°C and 20°C, conductivity between 870 µS/cm and 1270 µS/cm; and chlorine between 0 and 5 mg/L. Because of the high-level of electromagnetic interferences in Sense-City and limited shielding of the acquisition system, the sensor signal is severely noisy and various steps of denoising are required. From the initial dataset were extracted a small number of devices and time periods with both sufficient variations in the target parameters and manageable level of signal-over-noise ratio. For chip 141, over 150hours of testing, CNT-based chemistors showed sensitivity to pH and active chlorine (HClO) with differentiated response between functionalized and non-functionalized devices. However, pH and chlorine can only be estimated with MAE respectively 0.17 and 0.18mg/L due to the high noise level. Over 400h, with chip 141, the real-time temperature of the water can be estimated with an MAE of 0.4°C in flowing water and 0.1°C in static water. The chip 141 dataset did not feature enough conductivity variation to assess performances. This was achieved on chip AS001 with an MAE of 176.2 µS/cm over 80 hours.Overall, these results provide a preliminary proof of operation of the solution in realistic environment, with the high noise level being a major limitation. A new version of system is being designed to reduce the noise, to be tested in Sense-City in 2023.[1] Cousin, P. et al. (2022). Improving Water Quality and Security with Advanced Sensors and Indirect Water Sensing Methods. Springer Water. https://doi.org/10.1007/978-3-031-08262-7_

Real-time estimation of physiological properties of the cell during recombinant protein production would ensure enhanced process monitoring. In this study, we explored the application of dielectric spectroscopy to track the fed-batch phase of recombinant Escherichia coli cultivation for estimating the physiological properties, namely, cell diameter and viable cell concentration (VCC). The scanning capacitance data from the dielectric spectroscopy were pre-processed using moving average. Later, it was modeled through a nonlinear theoretical Cole-Cole model and further solved using a global evolutionary genetic algorithm (GA). The parameters obtained from the GA were further applied for the estimation of the aforementioned physiological properties. The offline cell diameter and cell viability data were obtained from particle size analyzer and flow cytometry measurements to validate the Cole-Cole model. The offline VCC was calculated from the cell viability % from flow cytometry data and dry cell weight concentration. The Cole-Cole model predicted the cell diameter and VCC with an error of 1.03% and 7.72%, respectively. The proposed approach can enable the operator to take real-time process decisions to achieve desired productivity and product quality.

13 figures, 5 tables.-- Appendix A. The impact of recovery rate on the DSPRO net pressure difference.-- © 2022. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/, Two-pass reverse osmosis desalination is a common process to treat high-salinity feed solution and provides a low-salinity permeate solution. This study investigated the significance of the energy generated by the dual-stage pressure retarded osmosis (DSPRO) from the reverse osmosis (RO) brine stream. The main components of the DSPRO-RO hybrid system are RO, pressure retarded osmosis (PRO), and energy recovery device, and their models are determined. Dymola software, using Modelica modelling language, was utilized for solving the hybrid system models. Two different flowsheets were built; the first included a two-pass RO, while the second is a hybrid of a two-pass RO (2RO)-DSPRO system. Seawater salinities of 40 and 45 g/L were the RO feed solution, and 1 g/L tertiary treated wastewater was the feed solution of the DSPRO process. The net specific energy consumption was calculated for the 2RO and 2RO-DSPRO systems for 40 and 45 g/L salinities. At a 47 % recovery rate and 40 g/L seawater salinity, the 2RO-DSPRO system was 14.7 % more energy efficient than the 2RO system. The corresponding energy saving at a 47 % recovery rate and 45 g/L seawater salinity was 17.5 %. The desalination energy for the 2RO system was between 3.25 and 3.49 kWh/m3, and for the 2RO-DSPRO system was between 2.91 and 2.97 kWh/m3. The results demonstrate the great potential of integrating the 2RO with the DSPRO to reduce desalination's energy consumption and environmental impacts., The authors wish to express their gratitude for the assistance provided by an Australian Government Research Training Program Scholarship. The RO-PRO pilot plant data used in this project was collected as part of the ongoing technology development project titled “Membrane-based efficient energy storage, clean energy generation, and wastewater treatment system”. This project is supported by the Department of Science and Technology, Government of India, Project Number No. DST/TMIWTI/2K16/73 (G).

Microplastics in the environment pose a significant threat to the entire ecosystem. Household activity, industrial activity, tyre wear and tear, construction, incineration, plastic litter, landfill, and agricultural activities are the major sources of microplastics in the environment. Microplastics can freely float and adapt between different environmental mediums in the ecosystem due to their lightweight and low-density characteristics. Eventually, microplastics entering the ocean from different pathways result in accumulation and widespread distribution in the marine environment. The frequent interaction between microplastic and aquatic environments accumulates the microplastics in live organisms. The microplastic accumulation and exposure to animals and humans will also affect the ecosystem. This chapter seeks to understand the sources, pathways, and abundance of microplastics in a different environment. The study also highlights the future research prospects for mitigation of plastic towards environment protection.

Membrane cleaning is critical for economic and scientific reasons in wastewater treatment systems. Sodium docusate is a laxative agent and removes cerumen (ear wax). Docusate penetrates the hard ear wax, making it softer and easier to remove. The same concept could be applied to soften and remove fouling layers on the membrane surface. Once softened, the foulants can be easily flushed with water. This innovative approach can address the challenge of developing superior methods to mitigate membrane fouling and material degradation. In this study, we evaluated the efficiency of sodium docusate for cleaning fouled forward osmosis membranes with real landfill leachate wastewater. Experiments were conducted to examine the impact of dose rate, contact time, flow or static conditions, and process configuration (forward osmosis (FO) or pressure retarded osmosis (PRO) upon fouling created by landfill leachate dewatering. A remarkable (99%) flux recovery was achieved using docusate at a small concentration of only 0.1% for 30 min. Furthermore, docusate can also effectively restore flux with static cleaning without using pumps to circulate the cleaning solution. Furthermore, cleaning efficiency can be achieved at neutral pH compatible with most membrane materials. From an economic and energy-saving perspective, static cleaning can almost achieve the same cleaning efficiency as kinetic cleaning for fouled forward osmosis membranes without the expense of additional pumping energy compared to kinetic cleaning. Since pumping energy is a major contributor to the overall energy of the forward osmosis system, it can be minimized to a certain degree by using a static cleaning approach and can bring good energy savings when using larger membrane areas. Studies of the contact angle on the membrane surface indicated that the contact angle was decreased compared to the fouled membrane after cleaning (e.g. 70.3° to 63.2° or FO mode and static cleaning). Scanning Electron Microscopy revealed that the cleaning strategy was successful. Infrared Spectroscopy showed that a small amount of sodium docusate remained on the membrane surface. Docusate is more environmentally friendly than acid or alkaline solutions from an environmental perspective. Furthermore, the cleaning solution can be reused for several cycles without discarding it due to the surfactant properties of docusate.

Membrane backwash is one of the most widely used membrane regeneration techniques in large-scale desalination operations and water and wastewater treatment applications. It is necessary in order to enhance membrane life and is critical in managing the cost of pure water. The estimation of optimal backwash conditions is very important for improved hollow fiber membrane (HFM) operations. A unique feature in HFM backwash operations is the lumen side pressure drop, which leads to variation in backwash water flow across the fiber length. In this work, the effect of fiber diameter, membrane structural properties and backwash water pressure and temperature on flow distribution across the membrane length is studied for HFM modules. An analytical model for HFM backwash is developed, and model predictions are compared with measured backwash water flow variation over the fiber length. Experimental results show that the backwash flow variation over the fiber length is minimized by maintaining low backwash water pressure. Simultaneously, minimum backwash flux for effective cleaning may be achieved by increasing backwash water temperature. Homogeneous flow distribution during backwash improves backwash efficiency or forward flow rejuvenation, which can also be achieved by optimizing fiber diameter and membrane permeability. The validated mathematical model may be used for the optimization of backwash operating conditions and HF dimensions to achieve homogeneous backwash flow distribution across the membrane length.

Dyes, organic solvents and oils pose a serious threat to the water resources and this is of immense global concern. For the removal of such harmful materials from wastewater, a novel aerogel was synthesized from a hydrogel precursor, formed by incorporating nano bentonite into the dialdehyde nanocellulose and carboxymethyl chitosan mesh. The material showed exceptional adsorption capacity towards diverse pollutants like dyes, organic solvents, and oils. This ultralight aerogel yielded maximum dye removal capacity up to 29.842 g g-1 and 20.927 g g-1 within the first 5 min of the reaction, over a wide range of pH towards Bromophenol blue and Direct Blue 6 respectively and up to 50 times of its own weight in case of oil and organic solvents. This eco-friendly aerogel showed a slight drop in the adsorption capacity after ten cycles of oil and organic solvents, which paves a path in its application in the removal of multiple classes of the pollutant from wastewater.

Tanker-based distribution systems have been prevalent in developing countries to supply clean and pure water in different regions. To efficiently operate such tanker service systems, a large fleet ...

Current study deals with the comparative assessment for efficient adsorption of Cr(VI) from simulated wastewater using raw (NPP), phosphoric acid-activated (PPP) and sulphuric acid-activated (SPP) Pongamia pinnata shells. Physico-chemical alterations of the adsorbent were characterised by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), zeta-potential analysis, energy-dispersive X-ray spectroscopy (EDS) and total pore analysis using Brunauer-Emmett-Teller (BET). Parameters influencing the efficient biosorption of Cr(VI) species viz. initial pH of Cr(VI) solution, dosage of biosorbent, biosorbent-Cr(VI) contact period, initial concentration of Cr(VI) ions and reaction temperature were optimised. Various two-parameter and three-parameter isotherm models, kinetic models and thermodynamic studies were performed using equilibrium data. Langmuir adsorption capacity for NPP (raw biomass), PPP (phosphoric acid-activated biomass) and SPP (sulphuric acid-activated biomass) was found to be 96.2, 152 and 192 mg/g, respectively. All the biosorbents gave best fit for pseudo-second-order model. Thermodynamic studies suggest spontaneous and endothermic interaction with increased degree of randomness. Effect of co-existing cations and anions on Cr(VI) biosorption onto the biosorbents implied that minimal competition and the biosorption capacity of the biosorbents for Cr(VI) species remained unaffected. Regeneration studies suggest that activated biosorbents can be used up to three times with continuous desorption.

Charcoal is a carbon-rich fuel produced predominantly from pyrolysis of wood. In this study, a natural draft-improved charcoal retort system was developed, and the produced charcoal has been analyz...

The low cost simplified method for implementation of pressure-assisted osmotic (PAO) backwash (BW) for spiral wound reverse osmosis (RO) membrane module is presented in this work. The effect of membrane design and an operating parameter concerning the efficiency of PAO membrane BW is analyzed. The following design and operating parameters are considered in this study: (i) spacer thickness, (ii) dimension of the permeate channel, (iii) number of leaves, and (iv) BW water pressure. The performance of PAO BW with respect to membrane cleaning efficiency is analyzed for three different high recovery RO systems by purifying 1,500 liters of water. The membrane cleaning efficiency is measured by examining the rate of permeate quality and quantity decline using ASTM D4516 method. Finally, to quantify the membrane fouling with respect to different high recovery configurations, the thickness, and composition of foulants present in the used membrane's surface are measured by using field emission scanning electron microscope with energy dispersive X-ray (FESEM-EDX). The result concludes that the RO membrane operated at high recovery with PAO BW is found to have less fouling deposits than membrane without PAO BW.

BACKGROUND: Greywater and produced water are undoubtedly valuable resources for reclaimed water, which can lessen the burden on use of freshwater. However, most often the membrane technology used for treatment of greywater and produced water suffers massively from fouling‐related issues. In the present study, a novel and facile method is successfully developed for modification of polypropylene (PP) microfiltration (MF) membrane via surface coating with sericin for imparting better antifouling properties. RESULT: The membrane hydrophilicity significantly improved after sericin coating and exhibited high water content (64.87%) and low water contact angle (38°). In a comparative study with synthetic greywater, the sericin‐coated membrane removed

BACKGROUND: Drug‐based micropollutants present in water sources are proven to be persistent, bioactive and toxic even at low concentration for human consumption. Therefore, the complete removal of the drugs from water is crucial to avoid long‐term medical complications. In the present study, a novel sericin‐coated adsorptive microfiltration (MF) membrane is used for the removal of drug‐based micropollutants. RESULTS: The sericin‐coated membrane was tested for removal of different classes of drugs from water. The membrane completely removed NSAIDs and antibiotics from water at 20 μg L⁻¹ concentration. The adsorption mechanism was profoundly influenced by charge‐based interaction and hydrogen bonding, hence charged anionic drugs were more effectively removed than uncharged drugs. In multidrug mixtures, the removal efficiency was observed in the following sequence; ibuprofen > diclofenac > amoxicillin > ciprofloxacin > estrone > β‐estradiol. Desorption of the drugs from the membrane surface can be effectively controlled by altering the pH of the membrane‐cleaning solution. Presence of other inorganic salts in the aqueous drug solution did not interfere with the removal efficiency of the sericin‐coated membrane. The performance of sericin‐coated membrane was studied using continuous adsorptive membrane filtration approach. The dynamic adsorption behavior of a fixed‐bed membrane column was predicted using Bohart–Adams model. The model can predict the adsorption breakthrough curve with minimum experimental error. CONCLUSIONS: This study reveals the unique application of sericin‐coated MF membrane for effective removal of drug‐based micropollutants from water, and demonstrates its easy regeneration and effectiveness for multiple cycles of filtration. © 2019 Society of Chemical Industry

Monitoring of water distribution network (WDN) requires placement of sensors at strategic locations to detect maximum contamination events at the earliest. The multi-objective optimization (MOO) of sensor placement is a complicated problem owing to its combinatorial nature, interconnected and large WDN sizes, and temporal flows producing complex outcomes for a given set of contamination events. In this study, a new method is proposed to reduce the complexity of the problem by condensing the nodal search space. This method first segregates the nodes based on intrusion events detected, using k-means clustering, followed by selecting nodes from each group based on the improvement observed in the objectives, namely, contamination event detection, expected detection time, and affected population. The selected nodes formed the decision variable space for the MOO study. The developed strategy was tested on two benchmark networks: BWSN Network1 and C-town network, and its performance is compared with the traditional method in terms of hypervolume contribution rate (CR) indicator and the number of Pareto points. The optimal subset of nodes generated twice the number of Pareto points than the complete set of nodes set for placing 20 sensors and had 10% more than CR indicator than the traditional method. For the placement of 5 sensors, the proposed solutions were better at the higher detection likelihood values, which is required to achieve maximum detection. The proposed sensor placement algorithm can be easily scaled to large WDNs. It is expected to provide a better optimal sensor placement solution irrespective of network size as compared to the traditional approach.

Identification and management of safe groundwater supply in a high As and F− contaminated region is a major concern facing most of the developing countries worldwide. This study provides a comprehensive hydrogeochemistry result for a complex hydro-stratigraphy soil aquifer, which is bound between the Shillong plateau and Himalayan ranges in the North-Eastern region of India. In this study, distinct contaminated regions of As and F− were identified in rainy (n = 94) and winter (n = 50) seasons groundwater samples. The maximum dissolved concentration of As was measured as 71 µg L− 1 in rainy and 211 µg L− 1 in winter season groundwater samples, whereas maximum F− concentration was measured as 7 mg L− 1 in rainy and 6 mg L− 1 in winter season groundwater samples. Identified minerals saturation condition, weathering, and dissolution results of hydrogeochemistry were well corroborated with the Bivariate plot, Gibbs and Pourbaix diagrams. Results of health risk assessment showed that population of age below 18 years old are prone to carcinogenic diseases and symptoms of non-carcinogenic health risk due to daily consumption of As contaminated groundwater. Children of age below 18 years old, in total 39% (i.e. 6834) and 64% (i.e. 13937) were found more susceptible to arsenic ingestion effect. The male population was found prone to As cancer risk than the female population. Overall, this study provides a critical result about the cause of high As and F− concentration in groundwater and health risk assessment, it provides a prime concern matter for the young generation which is at higher risk of As cancer.

Solar Fuels and chemicals from CO2 can be produced through two main reactions: one is CO2 photoreduction, using different catalysts and different reducing agents; the other is CO2 fixation, which is usually performed through natural photosynthesis. The research nowadays is directed on the production of fuels and chemicals with one or two atoms of carbon, for example CH4, CO, HCOOH, HCHO, CH3OH, C2H5OH, etc. The chapter aims at comparing natural photosynthesis processes and reactions with artificial photosynthesis. After taking into consideration the natural photosynthetic process, the chapter focuses on heterogeneous and homogeneous photocatalysis. Heterogeneous catalysis can be performed with semiconductors and powder catalysts. Special attention is given to TiO2 as a promising photocatalyst. Homogeneous photocatalysts are usually represented by molecular catalysts, which are dissolved in water or another solvent. Usually, homogeneous photocatalysis is performed in complex systems which are composed by: a light harvesting unit (LHU) (i.e. the photosensitizer); one catalytic site for the oxidation process, where the electrons are supplied by a sacrificial donor; one reduction site, where the electrons are transmitted to CO2. Finally, even more complex systems are represented by those based on photoelectrocatalysis. These have the main advantage to separate the oxidation and reduction reactions at the two different electrodes of the system. In principle photoelectrochemical cells can be a way to mimic artificially the working principle of natural photosynthesis.

Identification and management of safe groundwater supply in a high As and F– contaminated region is a major challenge. This study provides comprehensive hydrogeochemical investigation results for a complex hydro-stratigraphy controlled soil aquifer, which is bound between the Shillong plateau and the Himalayan ranges in the North-Eastern region of India. In this study, distinct contaminated regions of As and F– were identified in the post-monsoon (n = 94) and winter (n = 50) seasons groundwater samples. The maximum dissolved concentration of As was measured to be 71 µg L–1 in post-monsoon and 211 µg L–1 in winter season groundwater samples. Maximum F– concentration was measured as 7 mg L–1 in post-monsoon and 6 mg L–1 in winter season groundwater samples. Identified minerals saturation, weathering and dissolution condition results were well corroborated with the hydrogeochemistry, Bivariate plot, Gibbs and Pourbaix diagrams results. Children of age below 18 years old, in total 20% (i.e. 6,511) and 25% (i.e. 3,627) of the residents were found to be more susceptible to arsenic ingestion effect. The results of health risk assessment showed that the population of age below 18 years old are prone to carcinogenic diseases as well as a symptoms of non-carcinogenic health risk due to daily consumption of As contaminated groundwater. The male population was found relatively more prone to As cancer risk than the female population. Overall, this study provides a critical result about the cause of high As and F– concentration in groundwater and their health risk assessment. It seek to address a prime concern for the usage of groundwater source for drinking water in the Brahmaputra flood plain.

This work studied the optimal conditions for pyrolysis of Prosopis juliflora wood in fixed-bed tubular reactor. The optimal conditions are measured by performing pyrolysis experiment with respect to wood properties such as particle size, moisture and pyrolysis condition such as, temperatures, heating rates. Higher solid yield (36.8%) was recorded for a slower heating rate of larger particle size at lower temperatures. Further, higher liquid yield (38.3%) was observed while maintaining high heating rate and temperature. It is observed that with increase in particle size, the yield of char and gas decreases and bio-oil increases. The literature reported biomass pyrolysis kinetic model is validated for Prosopis juliflora wood. The kinetic models are able to predict the performance of fixed-bed tubular reactor in terms of pyrolysis product properties. The validated kinetic model may be used for the design of commercial fixed bed pyrolysis reactor to process Prosopis juliflora wood.

Severe fatigue and excessive load transmissions on drill strings during rotary drilling may lead to unexpected drill string failure. And if the driller within the stipulated time-bound did not control these load forces, the situation might increase NPT. To achieve the same by driller in real-time, the structural integrity of the tubular was monitored with a workflow that estimates the overall stresses acting along the drill string. In actual operating conditions, the drill string is subjected to both internal and external pressures, and it can be well explained in terms of true tension and effective tension. The estimation of these tensional forces and other load forces acting on the drill string is important for efficient drilling operation and the selection of optimum operational parameters. In addition, these forces are further utilized to estimate the neutral point and load acting at the deadline. The conventional rigs are subjected to numerous uncertainties that affect the precision of the hookload measurement at the deadline. Therefore, the factors affecting the hookload measurement at the deadline are summed up to a quantifiable metric labeled as Rig Uncertainty Compensation (RUC) factor. Further, the estimated hookload is compared with the actual hookload to detect the upcoming complications and prevent it from aggravation. And, to confirm the upcoming anomaly, the wellbore secondary drilling parameters are monitored in the real-time drilling operation. Additionally, all the forces acting along the drill string were also determined and monitored dynamically such that stress exposure in all the sections of the drill string is below a threshold value. To determine the efficacy of the developed model, the model was integrated with a Decision Support System (DSS) tool and tested in the actual field conditions. The tool was able to detect the upcoming complication successfully, and a field case study was presented in brief.

Drilling is one of the expensive operations in oil and gas production. The cost of drilling exponentially increases with an increase in non-productive time (NPT). Extending the drill bit life, reducing the NPT (minimizing downhole complications, round trips or bit trips, circulation time, etc.), and the total expended specific energy would reduce drilling costs. It can be achieved by increasing the rate of penetration (ROP) and optimizing drilling efficiency. This paper presents a novel approach for optimum drilling parameters based on real-time optimization of drilling rates, drilling efficiency, and bit hydraulics. And this can be visually substantiated by the play-back methodology employed on an exploratory well. To determine the inefficient drilling zones for different lithology, drilling specific energy (DSE), mechanical specific energy (MSE) was estimated at all operating conditions. The result shows that utilization of optimal drilling parameters reduces input power by nearly 75%. Further, in this study, a new metric termed hydraulic drilling impact (HDI) is introduced to optimize the drilling performance during real-time rotary drilling operations. Monitoring the HDI in actual field conditions can help the driller evaluate the ongoing drilling operation's reliability. Fallouts from the comparison disclose that the excessive energy spent for the low ROP was due to inappropriate drilling parameters chosen for a particular formation. This work can contribute to the effective and accurate evaluation of operating parameters and conditions by utilizing surface readings alone where no downhole sensors/equipment were employed. The proposed model was validated in a directional well that was drilled in the north-eastern parts of India.

The presence of microplastic particles from five different beach locations (Arabian Sea coast) in the Indian state of Karnataka was assessed. The sieving and density separation method was modified to enhance the yield of microplastics. Three different techniques were used to characterize isolated microplastics, such as optical fluorescence microscopy, Raman spectroscopy, and FESEM-EDX. Microplastic concentrations ranged from 264 ± 62 n/kg to 1002 ± 174 n/kg of dry sand in beach sediments, and the average abundance of the five beaches was 664 ± 114 n/kg. The majority of the microplastics were fragmented,1 mm in size, white and transparent in color. FESEM images of microplastics show the roughness, cracks, mechanical and oxidative weathering, indicating their continuous exposure in the environment. EDX spectra provide the presence of various elements on the microplastic surface.

This Article presents removal of ibuprofen from aqueous solution using commercially available silk sericin as an adsorbent in an integrated adsorbent-membrane process. The adsorption study was performed at different physiological conditions, such as adsorbent concentration (1–10g), ibuprofen concentration (10–70 mg/L), temperatures (20, 30, and 40 °C), and pH (5, 6, 7, and 8). The occurrence of adsorption before membrane separation was confirmed by performing analysis of sericin–ibuprofen interaction and complex formation. Sericin–ibuprofen interaction and complex formation was investigated using FTIR, FESEM, fluorescence spectroscopy, XRD, and ITC. Sericin and ibuprofen interaction is spontaneous and endothermic in nature, while random coil transition of Sericin governed the adsorption system. ITC analysis exhibited a binding affinity (Kb) value of 2.51 × 104 ± 1.4 and one binding site (n ≈ 1) per molecule at 27 °C, revealing moderate binding of ibuprofen to the sericin protein. Complete removal of ibupr...

This paper deals with the pyrolysis of Prosopis juliflora fuelwood using thermogravimetric analysis to determine the kinetic parameters at six different heating rates of 2, 5, 10, 15, 20 and 25°C/min. The activation energy of pyrolysis was calculated using different methods, namely Kissinger, Kissinger-Akahira-Sunose, Ozawa-Flynn-Wall and Friedman model and corresponding calculated activation energy were found to be 164.6, 204, 203.2, and 219.3kJ/mol, respectively for each method. The three-pseudo component model was applied to calculate the following three kinetic parameters: activation energy, pre-exponential factor and order of reaction. The experimental results were validated with model prediction for all the six heating rates. The three-pseudo component model is able to predict experimental results much accurately while considering variable order reaction model (n≠1).

A novel biosorbent Phanera vahlii fruit biomass (PVF) and its biochar and chemically modified forms were studied for the elimination of Cr(VI) from synthetic solutions. Biosorbents were characterized through BET, FTIR, FESEM, EDX, and TGA technique. The parameters influencing biosorption were optimized and found as pH 2.0, temperature 303 K, initial metal concentration 500 mg/L, and biosorbent dosage 0.5 g/L. The ideal contact time was 180 min for all biosorbents. Freundlich isotherm was found to have good correlation with investigational data, which indicated that biosorption takes place in multiple layer style. Langmuir adsorption isotherm yielded the highest biosorption capacity (Qo) to be 159.1, 225.1, 244.1, and 278.5 mg/g for Phanera vahlii fruit biomass, Phanera vahlii biochar, Phanera vahlii phosphoric acid activated carbon, and Phanera vahlii zinc chloride activated carbon, respectively. Experimental data had good correlation with pseudo-second-order kinetic model fitted. Thermodynamic studies indicated the biosorption process to be spontaneous, stable, and endothermic. Thus, it was concluded that Phanera vahlii fruit biomass and the derived activated carbons are promising biosorbents for adsorption of chromium from aqueous solutions.

Particulate matter and volatile organic compounds have emerged as a prime environmental concern with increasing air pollution in metropolitan cities leading to lung and heart-related issues. This paper describes a facile and novel method for fabrication of polyester based air filter via surface coating with Sericin for imparting effective removal of particulate matter and volatile organic compounds. A simple dip-coating method followed by thermal fixation has been adopted to coat Sericin on the polyester fiber. The developed changes in surface functionality and morphology of the polyester fiber were confirmed by Attenuated total reflection Fourier-transform infrared spectroscopy and Field emission scanning electron microscopy analysis. The fabricated air filter was tested for removal of particulate matter (generated burning incense stick) and volatile organic compounds (generated vaporizing gasoline), in an indoor chamber. The Sericin coated filter was able to remove the PM2.5 and PM 10 (from 1000 μg/m3 level to 5 μg/m3 in a 6.28 m3 chamber) within 27 and 23 min of operation, respectively. The fabricated filter very effectively removed particulate matter for 2160 cycles with intermittent washing. The Sericin-coated air filter also proved very effective for removal of volatile organic compounds (Benzene, Toluene, Ethylbenzene and Xylene) from an indoor chamber at a varying initial concentration of 100–1000 μg/m3. The adsorption behavior was described by Langmuir-Freundlich (sips) isotherm and pseudo-first order kinetics with minimal error. The maximum adsorption capacity (mg/g) obtained with Sips Isotherm fitting followed the order Xylene (6.97)>Ethyl Benzene (5.68)> Toluene (5.35) >Benzene (4.78).

The objective was to understand the effect of change in the composition of combustible (CC)/ non-combustible components (NCC) on the unstretched laminar burning velocity (LBV), burned gas Markstein length (Lb) and Lewis number (Le) of premixed producer gas (PG)-oxygen mixtures. Design of composition and flame stability aspects based on Le are presented in part-1. PG comprised of CC(CH4:CO:H2) + NCC(CO2:N2) and the extent of variation was identified from 800 compositions reported in 123 research works. In this work, forty-five PG mixtures were studied where CC:NCC varied from 25:75–45:55, CO2:N2 from 0:100–100:0 and CH4:CO:H2 from 25:25:50–50:25:25. Spherical flame method was used to measure the LBV at 1 bar, 300 K and ϕ = 0.8 in a 4.5L spherical chamber. Validation experiments were performed with (50%H2 + 50%CO)-air mixtures and it compared well with the literature and computational data. Unstable mixtures identified by effective (volume-based model) and critical Lewis numbers corroborated well with the experimental burned gas Markstein length.

Part-1 reported the extent of variation in each species in producer gas (PG) mixture(s) after a thorough literature study. Forty-five PG variants were identified to analyse the effect of each species on the combustion characteristics of PG-O2 mixtures. Spherical flame method was used for measuring laminar burning velocities and burned gas Markstein lengths of PG at 1 bar, 300 K and ϕ = 0.8 in a 4.5 L spherical chamber. Extrapolation (linear and non-linear) and non-extrapolation based schemes were used to estimate unstretched flame speed. LBV extracted from all three schemes were in good agreement within ±4.92%. Only H2/CO-rich-PG-O2 mixtures having mole fraction of combustible components (CC) less than 20% displayed negative Lb values and their effective Lewis numbers were less than the respective critical values and were corroborated with experimental results. CH4-rich-PG-O2 mixtures were unconditionally stable. Their LBV was the highest at most conditions due to high flame temperatures, with exception to LBV of H2-N2-rich-PG-O2 mixtures at 45%CC owing to large thermal diffusivities. LBV varied non-linearly as CO2 in non-combustible components (NCC) increased beyond 50% and its suppressing effect was the highest in CH4-rich-PG. Simulations were performed using 1D expanding spherical flame model in COSILAB with GRI-Mech3.0. Simulated LBV showed a deviation of ±13.2% with experimental values at 45%CC. Unstretched LBV obtained from non-extrapolation-mapping method which involved simulation results showed good agreement with experiments. Combustion of PG with higher H2, CO and N2 content and relatively lesser amounts of CH4 and CO2 were stable to preferential diffusion effects and predictable to fluctuations in composition.

The viability of the FO process for concentration of sugarcane juice by using a commercially available aquaporin embedded hollow fibre membrane module (HFFO) (active area, 2.3 m2) is presented. NaCl is used as a draw solution (DS), and the selection of suitable DS concentration, flow conditions and flow configuration are observed to be vital aspects to minimize the reverse solute flux (RSF) and energy consumption. Further, the one dimensional mathematical model for the batch and continuous FO process using HF module is developed and validated with experimental data within the error limit of 5% for water flux and RSF. Based on the flowsheet modelling, the method for establishing the optimized FO process is presented. The optimized FO flowsheet presented in this study can concentrate the sugarcane juice from 150 g L−1 to 531 g L−1 with energy consumption of 92.14 WL-1 of permeate and specific RSF = 1.57 g L−1. Further, to commercialize FO process for sugarcane juice concentration application, the selection of suitable food-grade draw solute that can provide high osmotic pressure and low RSF is a very important aspect.