Exploitation of Bentonite for Wastewater Treatment

Bentonite is a clay with interesting surface properties (affinity for water, adsorption capacity for electro-positive compounds….). The characteristics and clarifying properties of bentonite from various companies are the subject of numerous studies. The present work focuses on the study of the efficiency of bentonite and modified bentonite to purify aqueous solutions containing organic pollutants such as phenol. First, before starting the adsorption study, a physical–chemical characterization of the clay by FTIR, BET and XRD techniques was undertaken. The specific surface of the bentonite is calculated by BET. Then, the study of isotherms and kinetics of phenol adsorption on commercial BTC showed that this pollutant can be removed from liquid effluents with a significant percentage. Langmuir and Freundlich models were applied. Finally, the kinetic study performed by UV–Visible was reproduced by FTIR spectroscopy.

Value addition study on coker kero for producing alpha olefin and alkyl benzene

Coker kero stream is obtained from delayed coking which contains saturates with alpha olefins and PNA compounds which was physicochemical characterised. The fractions present in coker kero may be used further for value added products such as alkyl benzene and naphthalene etc. The study described potential of coker kero via aromatics and non-aromatics separation by using liquid-liquid extraction (LLE) with N-methyl pyrrolidone (NMP), acetonitrile and methanol as solvents of different polarity. Methanol imparts best colour improvement as per ASTM D-1500. Beside this, adsorption study on coker kero was performed using fuller’s earth, chalk powder, red ochre and wood-stick’s ash as adsorbents. The adsorption study suggested that fuller’s earth not only separate aromatics and non-aromatics form coker kero, but also acts as a better adsorbent than graphitic carbon (activated charcoal) and is found suitable for colour improvement comparatively. This study inferred the separation of polar components, improvement in the colour, odour and established the stable fuel. FT-IR study suggested that N-methyl Pyrrolidone gives better results comparatively other solvents. HC22 type analysis of coker kero raffinate and extract phase confirm the sharp extraction of coker kero feed using N-Methyl pyrrolidone as it is a good solvent for extraction of aromatics. GCMS and HRMS compositional analysis successfully performed for the coker kero and it is separated aromatic and non-aromatic fractions.

In Situ Green Synthesis of Mil-100(Fe) Modified Edta as an Enhanced Candidate Detoxifying Agent of Lead Heavy Metal (Pb) and Its Adsorption Characteristics

EDTA-modified MIL-100(Fe) (MIL = Matériaux de l′Institut Lavoisier) was successfully prepared in situ using an electrochemical method. The porous nature of the material and its high stability under intestinal and stomach conditions present it as a great candidate agent for lead detoxification. Kinetic and isotherm investigations revealed that the adsorption of Pb2+ ions in MIL-100(Fe)-EDTA followed a pseudo-second order kinetic model with a rate constant of 0.0109 g/mg.min and a Langmuir isotherm model with an adsorption energy of 31.29 kJ/mol. The synthesized MIL-100-EDTA showed three times enhanced performance than MIL-100(Fe) in Pb2+ adsorption study. Optimum adsorption was achieved at pH 3 at an initial concentration of 5 ppm and a contact time of 12 h, yielding adsorption efficiency and capacity of up to 86.65% and 3.68 mg/g, respectively.

Removal of Dyes Using Various Organic Peel-based Materials: A Systematic Review

This review recapitulates the recent adsorption study literature regarding the activated biochar and nanocomposites of agricultural peel-based bio-adsorbents for the removal of dyes from wastewater. The use of agricultural peel in decoloration technology is promising for efficiency, cost-effectiveness, and eco-friendliness. Various types of bio-adsorbents have been studied in the literature, such as orange peel, potato peel, banana peel, cucumber peel, Pomelo peel, and rambutan peel, respectively. The equilibrium data and kinetics were analyzed, and they fit known models are also summarized. This review article will help to know the applicability and potential of various peel-based bio-adsorbents in wastewater treatment. The conclusion has been drawn from the literature review, and few suggestions for further future studies are also proposed.