Krishna G. Bhattacharyya

• M. Sc., Ph. D., D.I.C.
• Professor at Gauhati University

Silver-doped-titanium dioxide nanoparticles supported on Fuller’s earth, prepared by the sol-gel method, were characterized with XRD, TGA, zeta potential, SEM, EDX, TEM, XPS, photoluminescence and UV-DRS measurements. The material, Ag-TiO2-Fuller’s earth (AgTF), was tested for photocatalytic activity concerning the degradation of rhodamine B (RhB)...

The exceptional electron transport mechanism involving layered double hydroxides (LDHs) have led visible light mediated photocatalysis to gain significant interest towards wastewater treatment. LDHs inherently have remarkable photocatalytic characteristics owing to their capability to vary the metal ions and its ratios in the interstitial regions,...

Clays are naturally occurring environment-friendly materials possessing high specific surface area and good cation exchange capacity. Montmorillonite, one of the widely available clays, is known for its accumulative capacity for water-soluble hazardous and toxic dyes on the surface. This can be further modified by introducing inorganic and/or organ...

Pollutants emerging from the effluents of paper mills eventually destroy the environment of our ecosystem. To find a proper solution of it, a cost-effective and environmentally benign technique is proposed here to remediate contaminants present in the effluent of paper mill in a sequential steps using advanced oxidation processes including Fenton r...

This study explores the possibility of developing an eco-friendly adsorbent for effective remediation of groundwater fluoride, a well-known health hazard affecting more than 25 nations on the various continents. A facile and milder approach has been adopted to synthesize chitosan-modified ZnO/ZnFe2O4 nanocomposites. The synthesized materials have b...

Copper is an essential micronutrient; however, as a result of its increasing demand, subsequent mining followed by its direct discharge into the environment has led to the contamination of our ecosystem. Thevetia peruviana (TP) is an ornamental herb of medicinal interest and is extensively used as an antipyretic and anticancer agent due to the pres...

The sediments in stormwater runoff are recognised as the major sink of the heavy metals and affect the soil quality in the catchment. The runoff sediments are also important in the management of contaminant transport to receiving water bodies. In the present work, stormwater during several major rain events was collected from nine principal locatio...

Layered double hydroxides (LDH) also known as hydrotalcite-like compounds that represent a broad class of lamellar basic inorganic compound possessing high capacity for anion intercalation. In this work, Mn/Ti LDH has been synthesized through a single step hydrothermal route using commercially available Mn(NO3)2.4H2O, TiCl4 and urea for investigati...

A preliminary assessment of groundwater quality for drinking and irrigational purposes in the lower Jia Bharali river catchment and adjoining areas of North Brahmaputra Plain, India, was carried out with respect to major cations, anions, and trace elements. Water samples from 50 shallow alluvial dug wells were collected in wet and dry seasons for a...

Fe/Ti-layered double hydroxide (LDH) has been hydrothermally prepared and characterized using X-ray diffraction, scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and UV–visible diffuse reflectance spectroscopy for evaluation of its structure, morphology, and optical properties. The purpose of doping Ti...

Euryale ferox Salisbury (E. ferox) is an environmentally and economically important wetland macrophyte. This paper investigates the adsorption of a carcinogenic dye, basic fuchsin in the aqueous phase onto the hard shell of Euryale ferox seeds so as to establish the thrown away residue as a novel, efficient, bio-friendly and economically low-cost a...

Over the years, heavy metal pollution has become a very serious environmental problem worldwide. Even though anthropogenic sources are believed to be the major cause of heavy metal pollution, they can also be introduced into the environment from natural geogenic sources. Heavy metals, because of their toxicity and carcinogenicity, are considered to...

Presence of dye molecules in water causes various harmful effects for both human and aquatic species. Herein, we tried to remove two cationic dyes, namely Crystal violet and Brilliant green, from water by kaolinite clay mineral. The kaolinite clay mineral is further treated with 0.25 M and 0.05 M H2SO4 to increase its adsorption capacity. The struc...

The present study envisages the application of multivariate analysis, water utility class and conventional graphical representation to reveal the hidden factor responsible for deterioration of water quality and determine the hydrochemical facies of water sources in Jia-Bharali river basin, North Brahmaputra Plain, India. Fifty groundwater and 35 su...

The aim of this study was to display distribution and relationships of heavy elements in the unconfined, shallow alluvial aquifers of the lower Jia Bharali catchment and adjoining areas in central part of North Brahmaputra Plain (NBP), India using hydrochemical as well as multivariate statistical techniques such as principal component analysis (PCA...

Waste water from textile and other industries containing dyes, especially azo dyes, are a serious health hazard. This study deals with removal of two least-studied anionic azo dyes, namely, Crocein orange G (COG) and Procion red MX5B (MX5B) from water with the help of montmorillonite and acid-treated montmorillonite. Structural changes of montmoril...

The sediments in stormwater runoff are recognised as the major sink of the heavy metals and affect the soil quality in the catchment. The runoff sediments are also important in the management of contaminant transport to receiving water bodies. In the present work, stormwater during several major rain events was collected from nine principal locatio...

Nanotechnology enabled air, water and wastewater treatment processes promise to overcome major challenges faced by the existing treatment technologies. New carbonaceous nanomaterials have been reported such as graphene nanosheets (GNs), single‐wall (SW) and multiwall (MW) carbon nanotubes (CNTs), and their functionalized varieties with high surface...

Increased anthropogenic activities due to modernization and fast growing civilization have immensely contributed to the contamination of water by heavy metals including iron. Iron, an essential element for living systems, occurs naturally in water. But when the iron concentration surpasses a definite tolerable limit, it becomes a matter of concern...

Polymer nanocomposites are hybrid organic-inorganic materials with at least one dimension of the filler phase that is less than 100. nm. Fillers enhance specific properties of polymers and polymer nanocomposites, particularly based on nanoclays, which have received wide attention due to their ability to improve mechanical, thermal, barrier, and fir...

The work describes an assessment of the major air pollutants, NO2, SO2, CO, O3, NH3, coarse and fine particulate matter (PM10, PM2.5) in ambient air in and around a 3 million tonne Petroleum Refinery and the possible impacts on a pristine area marked by the presence of the world-famous Kajiranga National Park, a world heritage site and habitat for...

Copper is a widely used metal known as micronutrient but poisonous metal to the living organism with a permissible concentration of 1.3 mg L-1 in aqueous solutions. It is necessary to provide a suitable, environment friendly and cost effective copper removal process to save the world. The adsorption technique is found to be an effective method for...

This study was carried out to investigate Arsenic (As) contamination in the alluvial aquifers of the lower Jia Bharali catchment and adjoining areas in Sonitpur district of Assam. Samples were collected twice a year (July and February) for three consecutive years from 50 monitoring wells spread into both older and younger alluvium between the Brahm...

Zn/Al layered double hydroxides having typical and interstratified arrangements have been synthesized by a single step hydrothermal method and by microwave assisted route. The LDHs have been characterized with respect to their structural and morphological aspects using PXRD, TG, CHN and SEM-EDX analyses. The mechanism of single anion interstratific...

Euryale ferox Salisbury (E. ferox) is an environmentally and economically important wetland macrophyte. This paper investigates the adsorption of a carcinogenic dye, basic fuchsin in the aqueous phase onto the hard shell of Euryale ferox seeds so as to establish the thrown away residue as a novel, efficient, bio-friendly and economically low-cost a...

Optically responsive, luminescent Ni/Co/Ti layered double hydroxide (LDH), synthesized by a single step hydrothermal route, exhibits highly efficient photodegradation of cationic and anionic dyes, Rhodamine B (~99.8 %) and Acid Red G (~99.6 %) respectively, better than that of commercial catalysts like NiO, CoO and TiO2. The LDH has been characteri...

A novel polymeric bioflocculant was produced by a bacterium utilizing degradation of n-hexadecane as the energy source. The bioflocculant was produced with a bioflocculating activity of 87.8%. The hydrocarbon degradation was confirmed by gas chromatography-mass spectrometry analysis and was further supported with contact angle measurements for the...

Aliphatic-aromatic hydrocarbons and heavy metals (Cd, Cu, Co, Cr, Ni, Pb and Zn) were estimated in soil and leaf samples of Machilus bombycina (host plant of Antheraea assama silkworm) plantation along with atmospheric benzene, toluene and xylene (BTX) concentration near the oil exploration region of upper Assam, India, during the pre-monsoon and p...

Luminescent Mn/Co/Ti LDH, synthesized by a single step hydrothermal route, has been found to be optically responsive for utilization as a highly efficient photocatalyst in destruction of the cationic dye Rhodamine B, in aqueous solution under visible light irradiation. The material has been found to be better than the commercial catalysts like MnO,...

Dried, mature leaves of Aegle Marmelos tree were converted to a powder, which was used as a biosorbent for dyes in water with methylene blue as a case study. The biosorbent had a surface area of 52.63 mg/g, and FTIR spectra showed the presence of –COOH, –NH2, –R–SC=O (thioester) and R1–S(=O, =O)-N(–R2, –R3) groups on the surface. The particles were...

The aim of this study was to assess the quality of surfacewater sources in the Jia Bharali river basin and adjoining areas of the Himalayan foothills with respect to heavy elements viz. (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) by hydrochemical and multivariate statistical techniques, such as cluster analysis (CA) and principal component analysis (PC...

Novel 3:1 Mn/Ti layered double hydroxide (LDH) for its application in visible light assisted photocatalysis to decolorize and degrade cationic and anionic azo dyes. A method for LDH synthesis and a method for visible light photocatalysis, performed on a specially designed photocatalytic device, applying the same are also disclosed.

Ti (IV) doped Ni (II) layered double hydroxide (LDH) of Ni/Ti ratio=3/1 with high crystallinity has been synthesized by co-precipitation of nickel nitrate and titanium tetrachloride from homogeneous solution which were demonstrated as efficient multifunctional catalyst. The catalyst has been characterized by P-XRD, FT-IR, solid state UV-Vis-DRS, TG...

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. After further consultation with the experts conducting research in the area of XRD and FTIR spectrum, it has been conclude...

Among all the renewable sources of energy, hydropower is the most potential source which is economical, non-polluting and eco-friendly. The efficiency of hydropower plant in the long run depends on many factors like water and sediment quality. Erosive and corrosive wear of machine parts like turbine is a complex phenomenon. The problem becomes more...

Analyses of fine particulates (PM2.5) from the upper Assam oil fields of India indicated considerable presence of higher hydrocarbons (C22-C35) and heavy metals, Cd, Co, Cr, Cu, Ni, Pb, and Zn. This has raised serious concern for the sustainability of the exotic Muga (Antheraea assama) silk production, which has been a prime activity of a large num...

Visible light responsive Ni/Ti layered double hydroxide (LDH) was synthesized by a single step hydrothermal route using commercially available Ni(NO 3) 2 .6H 2 O, TiCl 4 and urea which exhibited significant UV-visible absorption with a much narrower band gap (2.69 eV) that contributed significantly to the degradation of methylene blue under visible...

This work investigates the correlations existing among soil organic carbon (C), nitrogen (N), phosphorous (P), potassium (K), and physicochemical properties like clay mineralogy, textural components, soil aggregation, and land use pattern. Seven different locations were chosen in the tropical rainforest climate region of Assam, India, for the work....

Batch adsorption technique is utilized for the removal of Ni(II) ions in aqueous solution by jackfruit leaf powder (JLP) under different experimental conditions. Jackfruit (Artocarpus heterophyllus L., family Moraceae) leaf powder (JLP) has been prepared from clean, mature leaves of the tree, which are dried in the sun and in an air oven at 373-383...

2 : 1 Co/Ti layered double hydroxide (LDH) was synthesized hydrothermally using commercially available Co(NO3)2$6H2O and TiCl4, on a urea template. The high surface area material (�180 m2 g�1) had a narrow band gap (2.67 eV) and shallow and deep trap defect sites. The layered nanomaterial exhibited remarkable semiconductor properties and demonstrat...

Mature leaves of the neem tree (Azadirachta indica) were converted into fine powder, the neem leaf powder (NLP), which was used for adsorption of fluoride from water. Adsorption was 82.6% at pH 2.1, 97.5% at pH 7.0 and 99.4% at pH 10.0 at a fluoride concentration of 15 mg/L. Adsorption kinetics conformed to pseudo-second-order model with a rate coe...

Rapid urbanization and the consequent changes to urban traffic characteristics such as increased volume and congestion affect pollutant build-up on road surfaces as well as the top layer of soil (Zhao et al. 2010). In such cases, surface runoff accounts for quite a considerable contribution to the total runoff from land, and carries with it various...

In this work, several physicochemical properties of sub-tropical soil (up to 20 cm depth) like water holding capacity, organic carbon content, cation exchange capacity, texture, pH, and electrical conductivity were determined along with the trace metals, Co, Cr, Cu, Mn, Ni, Pb and Zn, in order to evaluate inter-relations among the trace metals and...

Inadequately treated effluents from industry have serious environmental and public health concerns. Even low level discharges create problems through accumulation in water and soil. In the present work, the pollutant accumulating capacity and the general environmental health status of soil which is a repository of treated and untreated effluent dis...

A bacterium isolated from the activated sludge of an oil refinery of Assam, India retained efficient bioflocculating activity through production of the bioflocculant when it was grown on a crude oil amended medium void of any other carbon source. The bioflocculating activity gained from the optimized medium broth was 86.2%, which could be enhanced...

Neem leaf powder prepared from mature, dried Neem (Azadirachta indica) leaves was investigated to assess its ability to remove fluoride from aqueous solutions using batch adsorption process. Effects of solution pH, contact time, adsorbent amount and solution temperature on fluoride sorption had been investigated. The biosorbent was effective at the...

The present study investigates the use of acid treated devdaru leaf powder (Polyalthia Longifolia) for adsorptive removal of arsenite from arsenite spiked distilled water. Adsorptions were studied at temperature 303K by batch processes. Rapid equilibrium was reached within 90 mins. The pseudo-second-order kinetic model was found to best correlate t...

The present study was carried out to evaluate the impact of the effluents and the solid wastes generated by a giant pulp and paper mill in the northeastern part of India on soil mineralogy of the area. The impacts were monitored by analysis of soil samples from seven sites located in the potential impact zone and a control site where any kind of ef...

Visible light responsive 2 : 1 Ni/Ti layered double hydroxide (LDH) was synthesized by a single step hydrothermal route using commercially available Ni(NO3)2·6H2O, TiCl4 and urea. The material exhibited significant absorption in the visible range with a very narrow band gap (2.68 eV). This could be attributed to structural defects as confirmed by d...

In this work, Mn(II), Co(II) and Ni(II) were incorporated into waste coal fly ash used as a catalyst support by refluxing with the appropriate aqueous salt solution. The materials were calcined at 773-873 K for 5 h and the amount of divalent cations entering into the fly ash was determined by AAS measurements. Further characterization included esti...

Pollution of water with anionic contaminants represents an important environmental concern due to the toxicity of these ions and their accumulation throughout the food chain. The fresh water wealth of India is under threat due to variety of natural and human influences. The high concentration of some toxic elements in anionic state such as fluorine...

One of the most common clay mineral, kaolinite was tested in this work as adsorbents for both a cationic dye, Methylene Blue and an anionic dye, Congo red. The clay mineral was further modified by treatment with 0.25 and 0.50 M H 2 SO 4. The influences of pH, interaction time, clay mineral amount and dye concentration on the adsorption process were...

Eight trace metals, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn, were measured in the urban soil of Guwahati City, Assam, India from 31 sites representing five different types of land use, residential, commercial, industrial, public utilities, and roadside. Cd and Co occurred in very low concentrations (Cd , but Cr had a significantly higher presence in indu...

The reaction of vanillin with 1.0% (w/v) aqueous NaOH solution to generate a new aqua and vanillin bridged polymeric sodium complex, [Na-2(H2O)(4)(vanillin)](2n) (1), is reported together with single crystal X-ray structure determination. The synthesized complex has also been characterized by elemental analyses, IR, H-1 and C-13 NMR spectroscopy an...

Various catalysts have been utilized for wet oxidation of organic compounds in water. Rhodamine B is a cationic xanthene dye, used in a large number of industries and is considered as an undesirable chemical in water. In the present work, commercially available metal oxides, MnO2, NiO and ZnO, and those activated by treating with 1.0 N H2SO4 were u...

Two of the most common clay minerals, kaolinite and montmorillonite, were allowed to interact with the cationic dye, Rhodamine B in aqueous solution. The clay minerals were used along with those modified by treatment with 0.25 and 0.50 M H2SO4. The influences of pH, interaction time, clay mineral amount, dye concentration and temperature on the ads...

This review deals with adsorption of metal ions, particularly those considered as hazardous, on clays and some inorganic solids and covers the publication years 2000-2013 describing and quantifying the use of isotherms to obtain the adsorption capacities of the solids. The inorganic solids in the review include clays and clay minerals, their modifi...

Catalytic wet oxidation has become one of the best options for mineralization of dyes in water. In this work, mineralization of methylene blue in water was tried by using raw and acid-treated (0.50, 0.75, 1.00 N H2SO4) MnO2 as oxidation catalysts. FT-IR, scanning electron microscopy, surface area and cation exchange capacity measurements were used...

Poly(cholesterylacrylatesulfone) (PCHAS) and poly(cholesterylacrylatesulfone-co-1-hexene)s (PCHASHs) at different ratios are synthesized from the monomer cholesteryl acrylate. The liquid crystalline phases are observed under a hot stage fitted with a polarizing optical microscope. The polysulfone and copolysulfones are characterized by FT-IR, 1H-NM...

The relationship between ambient concentrations of fine particulate matter (PM2.5) and detrimental effects on fauna remains a highly controversial issue. The present study has determined the levels of fine particulate matter and trace metals in the particulate matter as well as in soil and plants in an oil field of Assam in northeastern India in or...

Reactive dyes are widely used in industry to dye cellulosic fibres, nylon, silk and wool. Azo dyes and their precursors are generally considered as human carcinogens and their presence in water is also a known health risk. The present study investigates utilization of the commercially available clay mineral, montmorillonite K10, to remove Procion r...

Cu(II) was introduced into kaolinite and montmorillonite by impregnation and the resultant materials were calcined at 723 K for 360 min. Both Cu(II)-kaolinite and Cu(II)-montmorillonite were used as catalysts for oxidizing three chlorinated derivatives of phenol in water in presence and in absence of H2O2. The catalysts were characterized with AAS,...

Commercial ZnO, MnO2, and their acid-treated forms were used as catalysts for oxidative degradation of Orange II dye in water. ZnO and MnO2 were treated with 0.5, 0.75, or 1.0N aqueous H2SO4. The acid treated oxides were found to be highly effective in bringing about degradation of Orange II in water. As much as 68.7% of the dye in an aqueous solut...

This manuscript reports the synthesis of the liquid crystalline (LC) monomer cholesteryl 4-pentenoate and its sulfone and co-polysulfone with 1-hexene. The polymers were characterized by IR, 1H-NMR, differential scanning calorimetry and thermogravimetric analysis techniques. The LC phases were observed under a hot stage fitted with a polarizing opt...

The lower Jia Bharali catchment and adjoining areas in central part of North Brahmaputra Plain (NBP) is characterized by more than 800m thick Older and Younger Alluvium deposited by the west flowing Brahmaputra river and the south flowing trans Himalayan rivers. Unconfined, shallow alluvial aquifers of the area with a general southward flow are lar...

Rainwater runoff has been identified as a significant source of contaminants having tremendous impact on the receiving aquatic environment. In the present study, trace element transport by the surface runoff in the predominantly urban catchment of Guwahati city, India was monitored with a view to determine the chemical denudation rates of the land...

The Zn/Co/Fe-layered double hydroxide nanowires are synthesized via a reverse microemulsion method by using cetyltrimethyl ammonium bromide (CTAB)/n-hexane/n-hexanol/water as soft-template. For the purpose of synthesis of ZnSO 4 .7H 2 O, CoSO 4 .7H 2 O, Fe 2 (SO 4) 3 .7 H 2 O and urea were used as raw materials. The synthesized LDHs are characteris...

Ti-doped hierarchical Zn-layered double hydroxides (LDHs) with different Zn/Ti ratios have been synthesized by co-precipitation of zinc nitrate and titanium tetrachloride from homogeneous solution, which were demonstrated as efficient visible-light photocatalysts. Powder x-ray diffraction (PXRD), scanning electron microscope (SEM), high resolution...

The synthesis of polycholesterylmethacrylate and poly(cholesterylmethacrylate-co-1-hexene) at different monomer feed ratios with their liquid crystalline behaviours have been reported in this article. Liquid crystalline phases of the polymer and copolymers have been detected under the hot stage microscope and also by differential scanning calorimet...

Naturally occurring kaolinite and montmorillonite were treated with 0.25 and 0.50 M H2SO4 and the modified clays along with the parent clays were used as adsorbents for the dye, Congo red in water. Adsorption was carried out in batch process with pH, dye concentration, amount of clay mineral, interaction time and temperature as the experimental var...

The lower Jia Bharali catchment and adjoining areas in central part of North Brahmaputra Plain (NBP) is characterized by more than 800m thick Older and Younger Alluvium deposited by the west flowing Brahmaputra river and the south flowing trans Himalayan rivers. Unconfined, shallow alluvial aquifers of the area with a general southward flow are lar...

This manuscript reports the synthesis of the liquid crystalline (LC) monomer cholesteryl 4-pentenoate and its sulfone and co-polysulfone with 1-hexene. The polymers were characterized by IR, 1H-NMR, differential scanning calorimetry and thermogravimetric analysis techniques. The LC phases were observed under a hot stage fitted with a polarizing opt...

Naturally occurring kaolinite and montmorillonite were treated with 0.25 and 0.50M H2SO4 and the modified clays along with the parent clays were used as adsorbents for the dye, Congo red in water. Adsorption was carried out in batch process with pH, dye concentration, amount of clay mineral, interaction time and temperature as the experimental vari...

The Deepor Beel is a permanent, freshwater wetland at the southwest corner of Guwahati (India) and it is a major stormwater storage basin for the city. Beel was designated as a Ramsar site (No. 1207) in 2002 and recognized as an important habitat for a large number of migratory aquatic birds. Orchids of commercial value are also found in the forest...

A comparative assessment of the hydrological quality of the shallow aquifers and surface water sources in the Jia Bharali River basin and adjoining areas of the Himalayan foothills has been made in this work. Six set of seasonal samples were analysed with respect to the common physicochemical parameters including major anions (carbonate-bicarbonate...

Phosphates enter into water bodies mainly from non-point sources such as agriculture fields, which promote algal growth and cause eutrophication in lakes, wetlands, etc. Therefore, it is important to identify methods to reduce the level of phosphates in water bodies. In this work, we used kaolinite and its calcined and acid-activated forms as adsor...

The process of adsorption is considered to be one of the best water treatment technologies around the world. Different heavy metals, due to their toxic and hazardous nature, are possibly the most widespread groundwater contaminants imposing a serious threat to human health. In this review, an attempt has been made to discuss the use of two common c...

Toxic methylene blue dye is removed from water by accumulating it on the surface of clay minerals. Clay adsorbents are obtained from kaolinite, montmorillonite, and their acid activated forms. The adsorption experiments are carried out in a batch process in environments of different pH, initial dye concentration, amount of clay, interaction time, a...

A biosorbent was made from mature, dried Azadirachta indica (Neem) leaves, which was used for removal of Acid Blue 25 from aqueous solutions using the batch adsorption process. Effects of solution pH, temperature, agitation time, dye concentration and adsorbent amount on the adsorption process have been investigated. The biosorbent was effective at...

A biosorbent developed from waste leaves of Mango trees (magnifera indica) has been used for the removal of Cu(II) from aqueous solution. The use of the biosorbent, Mango lea powder (MLP) was evaluated with respect to the effects of pH, Cu(II) concentration, contact time, and biosorbent loading. The sorption dynamics were including kinetics and iso...

Mango (Magniferra Indica) Leaf Powder (MLP) was prepared as a biosorbent from the mature leaves of mango trees by thoroughly washing them with water, drying in an air oven at 373–383 K for 3–4 hours and grinding into a powder. The biosorbent, MLP, was obtained by separating the 50–100 mesh fractions, washing the same repeatedly with water to remove...

Interactions of Cu(II) ions with clays (kaolinite, montmorillonite and their acid-activated forms) were studied in an equilibrium batch process. The experiments were conducted with pH, interaction time, concentration of Cu(II) ions, amount of clay and temperature as the variables. More and more Cu(II) ions were held at the clay surface till precipi...

It is necessary to establish the rate law of adsorbate-adsorbent interactions to understand the mechanism by which the solute accumulates on the surface of a solid and gets adsorbed to the surface. A number of theoretical models and equations are available for the purpose and the best fit of the experimental data to any of these models is interpret...

The review provides research survey of phenol and its analogues in the environment including sources, environmental fate and effects on ecology and health. Work done in treatment of toxic and persistent phenolic compounds, for example, Fenton and Fenton like reactions, photo-Fenton reactions, wet oxidation and catalytic wet oxidation has also been...

In the present work, Azadirachta indica (neem) leaves were converted to a powder for use in the separation of Cu(II) ions from water. The powdered biomass was investigated as a sorbent for Cu(II) ions employing pH, time, initial Cu(II) ion concentration and the amount of sorbent as the experimental variables. At very low pH, Cu(II) ions were incapa...

As a part of a series of soil remediation experiments involving crude oil and different refined petroleum products in order to investigate the extent of degradation of the oil at a stipulated time and to identify the persistent components; remains of lubricating oil in soil were recovered by Soxhlet extraction in a 90 days experiment. Gravimetric d...

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The Assam region has been recognized only recently as one of the endemic fluorosis areas in India. Surveys indicate that one-seventh of the 700,000 people in the Karbianglong district of Assam have dental and/or skeletal fluorosis. For this reason, the high concentrations of fluoride (F) in the water resources in various areas of the district are o...

This work describes the results of assessment of the heavy metals, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn in urban soil of Guwahati City, India from 31 sites of five different land use types covering residential, commercial, industrial, public utilities, and roadside. Sequential extraction procedure was used to evaluate the relative distribution of the...

In an oil field oil from the wells is pumped to Group Gathering Stations (GGS) where the oil undergoes some treatment and is stored for transporting to refineries. A large number of contaminants including heavy metals enter into the nearby agricultural fields of a GGS through spills, leaks as well as through emissions from gas flaring and from effl...

Oil from the wells in an oil field area is pumped to a group gathering station (GGS) where the oil undergoes some treatment and is stored for transporting to refineries. Rudrasagar Oil Field in Assam has been a strong producing field being operated by the public sector ONGCL. Oil and other chemicals enter into the nearby agricultural fields through...

Removal of Pb(II) and Cd(II) from spiked water samples by adsorption on clays was studied in this work as a model for water treatment. Kaolinite and montmorillonite were used as the clay adsorbents and they were further activated by treating with 0.25 M H2SO4. All the adsorbents were characterized with respect to surface area, cation exchange capac...

Water pollution is one of the major concerns for human health. It is very much essential to analyze the underground water to study the variation in quality parameters. Based on the physico- chemical parameters, quality could be rated for various uses for the judicious effective use and get documented for the further references. In the present study...

Kaolinite and montmorillonite were modified with tetrabutylammonium (TBA) bromide, followed by calcination. The structural changes were monitored with XRD, FTIR, surface area and cation exchange capacity measurements. The modified clay minerals were used for adsorption of Fe(III), Co(II) and Ni(II) ions from aqueous solution under different conditi...

There has been a serious concern over the deterioration of pure drinking water quality in cities and towns. In developing countries, efforts to supply drinking water to their rural communities have focused primarily on digging deep tubewells and installing handpumps to exploit bacteriological safe groundwater. The present study aims at the assessme...

The Deepor Beel is a natural, freshwater wetland in the south-west corner of Guwahati, India. The Beel harbours a large number of migratory aquatic birds, especially in winter, and is a Ramsar site since 2002. The wetland provides livelihood to the people of the surrounding villages through collection and sale of fish, nymphaea nuts and flower, orn...