Browse

1 - 10 of 410 items :

  • Sustainable and Green Chemistry x
Clear All

Abstract

Studies on the adsorption of Pb(II) on plantain peels biochar (PPB) was conducted. The carbonized and activated, biochar was characterized using Braunauer-Emmett-Teller (BET) surface area and x-ray diffraction crystallography (XRD). BET analysis of the PPB indicated that the pore size (cc/g) and pore surface area (m2/g) was 8.79 and 16.69 respectively. Result of the XRD evaluated through Debye-Scherrer equation, showed a nanostructure with crystallite size of 14.56 nm. Effects of initial metal ion concentration, pH, and contact time were studied in a batch reaction process. Results showed that the adsorption of lead from aqueous solution increased with an increase in pH and initial concentration. Equilibrium modeling studies suggested that the data fitted mainly to the Langmuir isotherm. Adsorption kinetic data tested using various kinetic models fitted the Weber and Morris intraparticle diffusion model implicating pore diffusion as the main rate limiting step. The sorption studies indicated the potential of plantain peel biochar as an effective, efficient and low cost adsorbent for remediating lead (II) ions contaminated environment.

Abstract

Hormonal changes in humans and animals can be attributed to endocrine disrupting chemicals (EDCs). Studies have found that excessive exposure to natural and artificial environmental chemicals and toxins can have adverse effects on the endocrine system and reproductive health. The endocrine system creates and releases hormones that regulate the development of organs and how they function. Any disruption to hormones affects the development and functioning of the reproductive system, the brain and the neurological system. Research and reports on the subject have been published by international experts and organizations including the World Health Organization (WHO), United Nations Environment Programme (UNEP), International Labour Organization (ILO) and Endocrine Society. To fully comprehend the effect of EDCs on humans and wildlife, it is essential to understand epigenetics and its transgenerational effects on hormone development. Here, we extensively explore and review the research on the sources of EDCs, their effects and why exposure to EDCs is of concern, and treatments for EDC exposure.

Abstract

Single cell supercapacitors with electrodes of varying amounts of graphene and carbon black, formed via the electrospinning process with a carbon-based Polyacrylonitrile (PAN), were tested in 1M H2SO4. From the tested samples, the overall data indicates no correlation between impedance and capacitance energy values. However, the breakdown of the various samples showed mixed results of; good correlations between lower impedance resulting in higher and lower capacitance; while other samples showed higher impedance correlating to both higher and lower capacitance. No correlation was observed between the Impedance value and the thickness of the samples. Furthermore, carbon mole content was not a major factor in determining impedance; therefore, structure is not a major contributor to impedance. Whereas, carbon mole content is a major contributor to capacitance energy; Hence, impedance provides an alternative control point to increasing energy ( 2-10X times ), that can be retrofitted to existing systems, or to increase the energy storage beyond current levels by adjusting/controlling impedance in new designs. The data is indicating impedance is not constant and is varying. The mechanism of varying impedance is unclear and requires further research. However, it is thought to mimic the energy level and stability of matter (atoms). Therefore, impedance varies or oscillates accordingly to achieve an impedance level stability, and hence the term “Orbital Impedance Stability”. Thoughts into Impedance being an Energy Field, to be provided in next publication (In-sha’-ALLAH). This research is concluding that our conventional understanding of impedance is limited in scope. New approaches and further research is needed to better understand impedance behavior. A better understanding of impedance is essential to a breakthrough in energy storage devices from capacitors and batteries, to electric generation and distribution of energy, to magnetic levitation, medical drugs and other energy improvements.

Abstract

An experiment was carried out to study the effect of post-harvest dipping and various packaging materials on quality traits of mandarin at the laboratory of Project Implementation Unit (Citrus zone) Udayapur, Katari from January to February 2019. The parameters observed were physiological loss in weight, juice content, titrable acidity, total soluble solids, TSS/TA ratio and shelf life. The packaging materials include individual newspaper wrapping, perforated polyethene and corrugated box. Gibberellic acid with a concentration of 100 ppm was used as a dipping material. The experiment was laid out in Completely Randomized Design (CRD) with 8 treatment replicated 3 times. The result showed that among eight treatments combination, fruits treated with GA3 in combination with perforated polyethene recorded minimum physiological loss in weight (1.99%) and control (19.08%). High retention of juice content (40.30%), total soluble solids(12.83 brix) and titrable acidity (0.60%) was recorded in fruits treated with GA3 in combination with perforated polyethene in 24 days of storage. Fruits treated with GA3 in combination with perforated polyethene attained shelf life of 48 days followed by perforated polyethene with a shelf life of 44 days. Finding of the experiment may prove to be helpful in rural area to store mandarin with minimum loss as markets are far from the village.

Abstract

The aim of the study was to determine the effectiveness of leachates from municipal landfill co-treatment with the dairy wastewater in an aerobic membrane bioreactor. It was working in MSBR (sequential membrane bioreactor) systems twice daily and was equipped with the immersed membrane module installed inside what enabled its back-washing performance. The system was working. The concentration of activated sludge in the membrane bioreactor was equal to 4.0 g/dm3. However, the sludge load was at the level of 0.06 g COD/(g d.m. · d). The oxygen concentration was at the level of 3.0 g O2/m3. The share of leachate was varied in a range of 5 to 15 % vol. The evaluation of the effectiveness of the treatment process was based on the change of parameters characterizing the crude sewage and treated sewage. All analysis was carried out according to standards. Following parameters were determined: COD, BOD5, TOC and concentrations of phosphate phosphorus, total nitrogen and ammonium nitrogen. Chemical analysis is often not enough to define the degree of wastewater treatment. It was used toxicological research to determine the effect on the environment. Toxicity of wastewaters was measured using biotests with Vibrio fischeri and Daphnia magna. The results revealed that the volume of leachate in the treated mixture should not exceed 10 % vol. The following conclusion can be drawn from the present research - co-treated wastewater was not toxic. Landfill co-treatment with the dairy wastewater impacts on the effectiveness of biological wastewater treatment. Leachate includes substances which have low susceptibility to biodegradation; on the other hand, dairy wastewaters provide a lot of organic compounds, which can help to treat them.

Abstract

Pretreatment is an essential step in the conversion of lignocellulosic biomass into valuable products. It aims to increase the biomass susceptibility to enzymatic saccharification to generate fermentable monosaccharides. In this study, the efficiency of 2 % potassium hydroxide (KOH) solution used as a pretreating agent for various lignocellulosic feedstocks, such as corn straw, corncob, and poplar wood, was evaluated. The influence of the pretreatment time, which varied from 0.5 to 24 h at 50 °C, on the alteration of biomass composition was investigated, as well as the enzymatic digestibility. Finally, the overall sugar yields were determined. For corncob, the yield on average amounted to 453.9 ±18.9 mg·g−1 raw (untreated) biomass, regardless of the pretreatment time. The overall sugar yield for both the corn straw and poplar wood biomass increased with increased pretreatment time and ranged from 333.0 to 438.4 mg·g−1 raw biomass and from 123.2 to 215.7 mg·g−1 raw biomass, respectively. Based on the results obtained, the most appropriate pretreatment times for all types of biomass were proposed. The results of this study may be useful for the development of lignocellulosic biomass processing technology.

Abstract

In the present study, the creeks and lakes located at the western shore of Admiralty Bay were analysed. The impact of various sources of water supply was considered, based on the parameters of temperature, pH and specific electrolytic conductivity (SEC 25). All measurements were conducted during a field campaign in January–February 2017. A multivariate dataset was also created and a biplot of SEC 25 and pH of the investigated waters was performed. The average temperatures of the investigated waters were 0.10-8.10 °C. The pH values indicate that most of the water environments of the analysed area are slightly acidic to alkaline (5.26–8.50) with two exceptions: Siodlo II Creek (9.26) and Petrified Forest Creek (8.95), which are characterised by greater alkalinity. At the measurement points closest to the Baranowski Glacier and Ecology Glacier, SEC 25 values were the lowest (26.8–61.1 µS·cm–1), while the remaining values ranged from 79.0 to 382 µS·cm–1 for the whole studied area. Based on the results it is concluded that the periodic intensive inflow of ablation waters, combined with morphological changes in the glacier front, causes a significant variability in the outflow network, creating the conditions for changes in basic physicochemical parameters. Moreover, it is observed that local depressions in the terrain form sedimentation traps in which, alongside fine-grained deposits, compounds can accumulate that originate from in situ sedimentation and that are also associated with surface runoff from the melting of snow cover, buried ice and permafrost.

Abstract

Using survey, we discuss how climate and environmental issues awareness affects residents’ low carbon use behaviour. The results are following. Firstly, climate and environmental issues awareness positively affects residents’ low carbon use. Secondly, perceived effectiveness has mediate effect on the relationship between climate and environmental issues awareness and low carbon use behaviour partly. Thirdly, perceived value has negative moderate effect on the relationship between climate and environmental issues awareness and low carbon use conduct. The results of this study show that when residents feel higher perceived value about their low carbon consumption, they will engage in low carbon use even with lower climate and environmental issues awareness. It tells us that we should treat the residents differently with classification when advocate low carbon use. Specifically, there are some product and service in which consumers can gain high perceived value if the residents frugally use them with high efficiency. And we need to make effort to the following things: we improve the perceived value with hard working, and on the other hand, we make enough effort to enable the residents to deeply experience the perceived value via multiple means.

Abstract

The possibility of applying a colloidal solution of nanosilver in the closed circuit of pool water treatment as a complementary disinfectant with chlorine compounds was presented. The applied nanosilver solution is characterized, by hygienic certificate, as having a very high biocidal effect. Samples of pool water for the control were taken from 5 points of a pool circuit. The safety of the water was appraised by comparing the bacteriological and physicochemical test results with the admissible values specified by hygienic requirements. The results show that nanosilver solution can be successfully applied for precoating the filter bed and supporting the disinfection system. Special attention was paid to the bacteriological purity and stability of the disinfectant concentration. The influence of concentration of colloidal nanosilver (0-25 mg/dm3) on bacterial bioluminescence, crustacean mortality and macroscopic effect of root growth and seed germination of selected plants was analysed. The results obtained were related to the current knowledge on the impact of nanoparticles on indicator organisms. It was found that due to many still unknown mechanisms of interaction and transformation of nanoparticles in living organisms, further study of this issue is necessary.