Determination of Hexavalent Chromium (Cr(VI)) Concentrations via Ion Chromatography and UV-Vis Spectrophotometry in Samples Collected from Nacogdoches Wastewater Treatment Plant, East Texas (USA)

The concentration of hexavalent chromium (Cr(VI)), a toxic environmental pollutant and carcinogen, was determined in samples collected from Nacogdoches Wastewater Treatment Plant (NWWTP) using ion chromatography and UV-visible spectrophotometry (IC, UV-Vis). On reaction with 1,5-diphenylcarbazide (DPC) Cr+6 forms a 1,5-diphenylcarbazide-Cr(VI) complex, which is then analyzed at 530 nm and 540 nm, respectively. Via ion chromatography Cr(VI) concentrations were in the range of 0.00190±0.0020 and 0.0010±0.0006 ppm at the influent and effluent, respectively. With the use of standard addition wastewater samples were spiked with a 0.5 ppm Cr(VI) standard of various amounts and subsequently analyzed with UV-Vis spectrophotometry. The spiked concentrations gave Cr(VI) concentrations in the range of 0.0090±0.0060 ppm and 0.0040±0.0061 ppm at the influent and influent wastewater, respectively. The determined Cr(VI) concentrations through the ion chromatography and UV-Vis spectrophotometry are below the maximum USEPA contaminant concentration of 0.1 ppm. From the analysis, the NWWTP efficiently removes Cr(VI) before discharge into the environment through La Nana Creek. The removal efficiency for Cr(VI) was determined to be ≥92.8% along the wastewater treatment stages from the influent (aeration stage) to the effluent stages prior to discharge into the La Nana Creek.

Utilization of Cellulose from Luffa cylindrica Fiber as Binder in Acetaminophen Tablets

Cellulose is an important pharmaceutical excipient. This study aimed to produce cellulose from the fiber of Luffa cylindrica as an effective binder in the formulation of acetaminophen tablets. This study was divided into three phases, namely, (I) preparation of cellulose from Luffa cylindrica, (II) determination of the powder properties of the LC-cellulose, and (III) production and evaluation of acetaminophen of the tablets produced using LC-cellulose as binder. The percentage yield of LC-cellulose was 61%. The values of the powder properties of LC-cellulose produced show fair and passable flow properties and are within the specifications of a powdered pharmaceutical excipient. The mean tablet hardness and disintegration time of the LC-cellulose tablets have a significant difference in the mean tablet hardness and disintegration time of the tablets without binder; thus the cellulose produced improved the suitability of acetaminophen in the dry compression process. However, the tablet properties of the tablets produced using LC-cellulose as binder do not conform to the specifications of the US pharmacopeia; thus the study of additional methods and excipients is recommended.

Modified Cenospheres as an Adsorbent for the Removal of Disperse Dyes

The main objective of this investigation was to use modified cenospheres for the removal of disperse blue 79:1 (DB) and disperse orange 25 (DO) dyes from aqueous solution by batch adsorption process under different conditions (pH, adsorbent dose, adsorbate concentration, agitation speed, contact time, and temperature). Modified cenosphere was capable of removing up to 78% of DB and 81% of DO dyes from aqueous solutions of 40 mg/L dyes concentration. The investigated data was explained by the Langmuir isotherm. The experimental data were found to follow the pseudo-second-order kinetic model. The results of this study suggested that modified cenospheres could be used as a low-cost alternative to expensive adsorbents like activated carbon in wastewater treatment for the removal of disperse dyes.

Temperature Induced Aggregation and Clouding in Humic Acid Solutions

Humic acids in aqueous solution demonstrate inverse temperature-solubility relationships when solution conditions are manipulated to reduce coulombic repulsion among the humic polyanions. These effects were followed by dynamic light scattering (DLS) measurements of the resulting aggregates, as well as the addition of a polarity sensitive fluorescent probe (pyrene). The humic solutions could be primed for temperature induced clouding by carefully lowering the pH to a point where hydration effects became dominant. The exact value of the cloud point (CP) was a function of both pH and humate concentration. The CPs mostly lay in the range 50–90°C, but DLS showed that temperature induced aggregation proceeded from approximately 30°C onward. Similar effects could be achieved by adding multivalent cations at concentrations below those which cause spontaneous precipitation. The declouding of clouded humate solutions could be affected by lowering the temperature combined with mechanical agitation to disentangle the humic polymers.

Water Quality Assessment of the Central Himalayan Lake, Nainital

The Nainital Lake, situated in the central Himalayas of India, is an important water body and a major tourist spot. This study aims to identify factors or processes that determine the water quality of the lake. For this purpose, water samples from two different points were collected—highly polluted (Mallital) and least polluted (Tallital)—to represent the actual level of pollution in the lake in four different seasons (January, April, July, and October). The collected samples were analyzed for different physical and chemical parameters. In order to assess the state of the lake’s water quality, the samples were compared with the standard water quality values. Turbidity, electrical conductivity, total alkalinity, and heavy metal (lead, iron, and copper) concentration were found to be above the desirable limit of the prescribed national and international standards in all four seasons at both Mallital and Tallital. Reasons affecting the water quality were found to be natural (thermal stratification and lead-bearing rocks) and anthropogenic (domestic sewage, runoff, and illegal construction activities in the vicinity of lake). Various lake restoration alternatives/interventions have been suggested that can lead to an improvement in the lake’s water quality, such as afforestation, phytoremediation, and sediment basin.

Environmental Informatics and Soft Computing Paradigm: Processing of Cocos Nucifera Shell Derived Activated Carbon for Treatment of Distillery Spent Wash—A Solution to Environmental Issue

Soft computing techniques are very much needed to design the environmental related systems these days. Soft computing (SC) is a set of computational methods that attempt to determine satisfactory approximate solutions to find a model for real-world problems. Techniques such as artificial neural networks, fuzzy logic, and genetic algorithms can be used in solving complex environmental problems. Self-organizing feature map (SOFM) model is proposed in monitoring and collecting of the data that are real time and static datasets acquired through pollution monitoring sensors and stations in the distilleries. In the environmental monitoring systems the ultimate requirement is to establish controls for the sensor based data acquisition systems and needs interactive and dynamic reporting services. SOFM techniques are used for data analysis and processing. The processed data is used for control system which even feeds to the treatment systems. Cocos nucifera activated carbon commonly known as coconut shell activated carbon (CSC) was utilized for the treatment of distillery spent wash. Batch and column studies were done to investigate the kinetics and effect of operating parameter on the rate of adsorption. Since the quantum of spent water generated from the sugar industry allied distillery units is huge, this low cost adsorbent is found to be an attractive economic option. Equilibrium adsorption date was generated to plot Langmuir and Tempkin adsorption isotherm. The investigation reveals that though with lower adsorption capacities CSC seems to be technically feasible solution for treating sugar distillery spent. Efforts are made in this paper to build informatics for derived activated carbon for solving the problem of treatment of distillery spent wash. Capsule. Coconut shell derived activated carbon was synthesized, characterized, and successfully employed as a low cost adsorbent for treatment of distillery spent wash.

Mucin Reactivity after Acute Exposure to Mercury and Zinc Chloride in Neurocytes of Freshwater Snail Bellamya bengalensis: A Histochemical Study

Central nervous system (CNS) of gastropods is extensively studied for its pathology and immunocytology; there is scanty information on histochemical alterations in neuronal cells due to heavy metal. This study was designed to investigate histochemical alterations in cerebral neurons of freshwater snail Bellamya bengalensis after intoxication with mercuric chloride (HgCl2) and zinc chloride (ZnCl2). As per chemical components cerebral ganglia of Bellamya bengalensis showed three different zones, namely, periganglionic connective tissue sheath, interperikaryonal space, and neuropil. After intoxication, increased acidic content in extracellular matrix (ECM) of neuronal cells was found. These alterations were directly proportional to time of exposure period. From results, HgCl2 proved its highly toxic nature over chemical composition of cerebral neuronal cells of freshwater snail Bellamya bengalensis compared to ZnCl2 intoxication.

Two-Phase Dechlorination/Detoxification of Lindane (Hexachlorocyclohexane)

Dechlorination of lindane was carried out in a two-phase reaction. In first phase Devarda’s alloy and sodium borohydride were used in aqueous/ethanol reaction media. The reaction duration and temperature were optimized. In first phase higher dechlorination (78%) was achieved at 80°C with 40-minute reaction time and the products were chlorobenzene, dichlorobenzene, and chlorocyclohexane. In second phase, Ca(OH)2 and sulfur were added in reaction media. The reactions conditions like temperature and reaction time were optimized. After 30 minutes, dechlorination was enhanced from 78% to 94% and the final products were benzene, phenol, catechol, benzenethiol, cyclohexane, cyclohexanol, and cyclohexanethiol. The results suggested that dechlorination of lindane in first and second phase was carried out through hydrodechlorination and substitution reactions, respectively. The developed method was applied for lindane containing real wastewater and higher dechlorination (91%) was achieved under optimized reaction conditions.

Experimental Design of Photo-Fenton Reactions for the Treatment of Car Wash Wastewater Effluents by Response Surface Methodological Analysis

Establishing a treatment process for practical and economic disposal of car wash wastewater has become an urgent environmental concern. Photo-Fenton’s process as one of the advanced oxidation processes is a potentially useful oxidation process in treating such wastewater. Lab-scale experiments with UV source, coupled with Fenton’s reagent, showed that hydrocarbon oil is degradable through such a process. The feasibility of photo-Fenton’s process to treat wastewater from a car wash is investigated in the present study. A factorial design based on the response surface methodology was applied to optimize the photo-Fenton oxidation process conditions using chemical oxygen demand (COD) reduction as the target parameter to optimize. The reagent (Fe2+ and H2O2 concentration) and pH are used as the controlling factors to be optimized. Maximal COD reduction (91.7%) was achieved when wastewater samples were treated at pH 3.5 in the presence of hydrogen peroxide and iron in amounts of 403.9 and 48.4 mg/L, respectively.

Defluoridation with Locally Produced Thai Bone Char

The fluoride sorption ability of a locally available bone char is quantified. Both a synthetic solution and natural groundwater samples from several sites are studied and compared to Indian bone char, which is widely accepted and used successfully in India and elsewhere. The Freundlich and Langmuir sorption isotherms were used to quantify sorption properties. Results show that the Thai bone char is as effective as the Indian bone char for removing fluoride from contaminated water, despite the more rigid physical and social constraints found in rural Thailand. Sorption studies with fluoride-contaminated natural groundwater samples also show that chlorides, nitrates, and sulfates had little effect on the removal of fluoride by the homemade bone char.