Rajeev Kumar Dohare

Bio: Rajeev Kumar Dohare is an academic researcher from Malaviya National Institute of Technology, Jaipur. The author has contributed to research in topics: Membrane & Membrane distillation. The author has an hindex of 8, co-authored 32 publications receiving 221 citations. Previous affiliations of Rajeev Kumar Dohare include Defence Research and Development Organisation.

A Critical Review On Heavy Metals Removal Using Ionic Liquid Membranes From The Industrial Wastewater

Abstract: • Heavy metals like Hg, As, Pb, Cr, Cd, Zn, etc. have been discussed in this article. • Comparison of BLM, ELM and SLM has been studied. • SLM shows higher potential than other liquid membranes due to stability. • ILs when combined with SLM improves separation efficiency. • [THTDP]Cl, [Omim + ] [BF 4 − ] and [MTOA + ] [Cl − ] were common ILs for heavy metal removal Toxic heavy metals create several hazardous impacts on the environment and human lives. Certain heavy metals like Hg, As, Pb, Cr, Cd, Zn, Co, Ni, and many others have been discussed in this article. This review article discusses several water treatment technologies like reverse osmosis, nanofiltration, ultrafiltration, microfiltration, electrochemical, and physio-chemical processes. Fouling, scaling, and operating costs are the major problems of conventional membrane technologies. Selectivity, single-stage operation, and efficacy make liquid membrane an effective method for separation. Liquid membranes have been an exciting research area for various liquid-liquid and gas-liquid separation processes. In this aspect, modified supported liquid membranes like supported ionic liquid membranes (SILMs) emerge as a strong contender. In SILMs, ionic liquid plays a crucial role as the carrier. Various interesting properties of ionic liquids like negligible vapor pressure, liquid at room temperature, and versatile operations make working in extreme conditions. This paper emphasizes the possibility of various heavy metals that can be removed using SILMs. This paper compares the conventional separation techniques with liquid membranes like a bulk liquid membrane, emulsion liquid membrane, and supported liquid membrane.

Comparative study of arsenic(V) removal from aqueous solution using Aliquat-336 and 2-ethyl hexanol through emulsion liquid membrane

Abstract: One of the concerns of the world today is the contamination of water bodies by arsenic. Emulsion liquid membranes (ELM) resemble a promising alternative to the current separation processes, demonstrating various points of interest in terms of effectiveness, selectivity, and operational expenses. For the design of emulsion liquid membrane, the most significant step toward productivity is the selection of the surfactant and its concentration. In this work, emulsion liquid membrane was used to remove As(V) from aqueous solution. The emulsion was prepared with the help of Aliquat-336 or 2-ethyl hexanol as extractant, kerosene as a diluent and Span-80 as an emulsifying agent. Sodium hydroxide (NaOH) was used as an internal phase. It was found that extraction performance of Aliquate-336 is 78.45% whereas 2-ethyl hexanol is 87.5%. This indicates that 2-ethyl hexanol is better extractant in comparison to Aliquate-336. The surface tension value of membrane phase has also been studied to analyze the effect of extraction rate.

Mathematical and CFD modeling of vacuum membrane distillation for desalination

Abstract: In this work, a mathematical model has been developed for vacuum membrane distillation incorporating molecular diffusion–Knudsen diffusion–Poiseuille flow and validated with the experimental data. The feed-side membrane surface temperature used in mathematical model was estimated by computational fluid dynamics modeling. The effects of different operating parameters such as feed flow rate, feed bulk temperature, inlet concentration, and permeate-side pressure on water flux and salt rejection have been studied using PTFE membrane. It has been shown that with variation in feed flow rate from 0.5 to 2 lpm, the permeate flux increased from 20.1 to 25.6 kg/m2 h. Similarly, with increase in feed bulk temperature from 40 to 60°C, the permeate flux increased from 2.10 to 26.6 kg/m2 h. The permeate flux showed the variation from 17.8 to 19.5 kg/m2 h on decreasing permeate pressure from 7 to 5.5 kPa. No significant effect of feed salt concentration was observed on permeate flux. More than 99% rejection was ...

Continuous Fixed-Bed Adsorption of Heavy Metals Using Biodegradable Adsorbent: Modeling and Experimental Study

Abstract: In this study, a continuous fixed-bed column was investigated for heavy metal removal using modified wheat bran as adsorbent. Clay and chitosan were used as binders with the adsorbent to pr...

Brine management (saline water & wastewater effluents): Sustainable utilization and resource recovery strategy through Minimal and Zero Liquid Discharge (MLD & ZLD) desalination systems

Abstract: Brine is a saline water present in the natural environment and produced by desalination and other process industries such as the oil & gas, textile, leather, food, dairy, agriculture, and pharmaceutical industries. Although brine was designated to be discharged in the early stages of the brine management strategy, its environmental impacts have recently prompted the adoption of a new management approach. This change is the shift from disposal to utilization and resource recovery. Apart from being a source of freshwater, brine can also be a source of salts, minerals, metals, chemicals, bioactive compounds, and even energy (known as ‘osmotic power’, ‘salinity gradient power’ or ‘blue energy’). Minimal Liquid Discharge (MLD) and Zero Liquid Discharge (ZLD) systems can be employed for the treatment and recovery of valuable resources. This review article is the first to investigate and evaluate the potential of recovering all of the resources present in brine through its treatment and utilization in MLD/ZLD systems. Overall, the challenges, research gaps, and future prospects are identified through this analysis, with the ultimate goals of decarbonized and sustainable brine management.

Banana peel as a biosorbent for the decontamination of water pollutants. A review

Abstract: Pollution of environmental waters and ecosystems is increasing. Adsorption is an effective technique for water decontamination, but is limited by the cost of commercial adsorbents such as activated carbon. Research has thus focused on the recycling and transformation of biowaste as low-cost, biodegradable adsorbents. In particular, banana peel is promising for commercial use due to its wide availability and efficiency. Here, we review the use of natural banana peel for the biosorption of pollutants from water. We discuss the factors controlling pollutants removal, and the regeneration and reuse of the biosorbent. pH of 5.0 to 7.0 is favorable for the removal of cationic pollutants, while pH of 2.0 to 4.0 is suitable for anionic pollutants. Generally, higher pollutant concentration induces lower removal, whereas higher banana peel dosage induces higher removal. Banana peel exhibits efficient removal of pollutants at various temperatures, with adsorption capacities mostly within 1–100 mg/g. Nitric acid is the most efficient eluent for heavy metal desorption from banana peel. Most studies showed efficient biosorbent reuse up to five cycles and above. We also discuss the thermodynamics, kinetics and isotherms of the adsorption process.