Chemical Reports

Concentration levels and pollution status of selected heavy metals in active dumpsites in Port Harcourt, Rivers State, Nigeria

Tue, 05 Mar 2024 10:15:51 +0800

This study was carried out to assess the extent of concentration exposure of As, Cu, Cr, Ni and Mn in the soils of five active dumpsites located at (Eliozu, Oyibo, Eneka, Eleme and Woji) in the city of Port Harcourt Rivers State, Nigeria to evaluate the pollution indices of heavy metals. Soil samples were collected randomly at the quadrant from the dumpsite while control samples were collected from farmland 25 km away from the dumpsite. Some physiochemical parameters (pH, TOC and CEC) of the soils were evaluated using standard techniques, while the heavy metal concentrations were evaluated using Atomic Absorption Spectroscopy (AAS). The pollution levels of soil heavy metals were assessed using several pollution indices. The mean concentration of heavy metals (mg/kg) ranged between As (ND – 0.45), Cr (ND – 2.21), Cu (6.05 – 51.87), Mn (3.24 – 37.91), Ni (ND – 13.50) across the studied dumpsites. The heavy metal levels in soil samples observed were in the order of Cu > Mn > Ni > Cr > As (Eleme), Cu > Mn > As > Ni > Cr (Eliozu), Cu > Mn > Ni > Cr > As (Eneka), Cu > Mn > Cr (Oyigbo), Cu > Mn > Ni > Cr > As (Woji), Cu > Mn > Ni > Cr > As (Control Site). The pH results were relatively acidic across the studied dumpsites ranging from 5.7±0.58 to 6.63± 0.02, while the TOC levels were low to moderate showing no wide disparity in the values. The Cation exchange capacity (CEC) showed a range of 13.98±0.186 (Eneka) to 20.98±0.061 cmol/kg (Woji) across the studied dumpsites. The Igeo values except for Ni, Cu and Mn at Eneka dumpsite, Cr and As in all the studied dumpsites revealed moderate to heavy contamination. Pollution load index (˃ 1) was in the studied dumpsites which implies that there is heavy metal pollution across the studied dumpsites. Anthropogenicity indicates that human activity is mostly responsible for the increase in metals in the studied area. Low ecological risk indices for the heavy metals (Ni, Cu, Cr, Mn, As) were found in all the sampling locations except for copper in Oyibo dumpsite. According to the findings, there is a low to moderate level of heavy metal pollution in the soils from the dumpsite, which can deteriorate the food ecosystem if adequate measures are not put in place.

Chemical fractionation and mobility factor of some heavy metals in refuse dumpsite soil in Awka Metropolis, Anambra State, Nigeria

Ogochukwu J. Okakpu, Patrice A. C. Okoye, Theresa U. Onuegbu — Fri, 02 Feb 2024 10:18:50 +0800

The geochemical forms of some heavy metals in refuse dump soils at Agu-Awka, Awka metropolis was studied in order to assess the mobility and bioavailability of the metals and hence their potential environmental risk. Exchangeable fraction (F1) contained the % fraction of 13.23% for Cd, 17.43% for Cr, 14.63% for Pb, 12.40% for Ni, 25.34% for Zn and 15.92% for Mn and these are in the order of Zn ˃ Cr ˃ Mn ˃ Pb ˃ Cd ˃ Ni. The carbonate fraction (F2) contained the % fraction of 17.08% for Cd, 17.84% for Cr, 9.20% for Pb, 28.32% for Ni, 13.76% for Zn and 8.49% for Mn and these are in the order of Ni ˃ Cr ˃ Cd ˃ Zn ˃ Pb ˃ Mn. Lead was predominantly associated with organic fraction with a result of 42.64% followed by chromium and manganese with the values of 22.48% and 20.00% respectively. The organic bound metals were in the abundance trend of Pb ˃ Cr ˃ Mn ˃ Cd ˃ Ni ˃ Zn. The highest values of metal in Fe-Mn oxide phase was manganese with a value of 32.18%, followed by cadmium with the value of 21.76%. The values of the other metals bound to this phase were 17.52%, 16.64%, 13.99% and 12.90% for Zn, Ni, Cr, and Pb respectively. Zinc with the value of 32.20% was predominantly associated with the residual fraction. The other metals bound to this phase had their values to be 30.13% for cadmium, 28.24% for chromium, 20.61% for lead, 29.41% for nickel and 23.37% for manganese. The mobility factor values of the metals were relatively low and they followed the order of Ni > Zn > Cr > Cd > Mn > Pb. That notwithstanding, soils from studied area should be carefully monitored to prevent the release of these metals due to redox reactions which may make them available to plants through absorption.

Effect of organic manures and micronutrients on seed production of carrot (Daucus carota L.)

Asha Dhaka, D.K. Yadav, Pooja Dhaka, Kaushalya Choudhary — Tue, 20 Dec 2022 14:57:15 +0800

The experiment was conducted during 2021-22 in rabi season. The field study to assess the effects of organic manures and micronutrients on seed production of carrot (Daucus carota L.) cv. Pusa Rudhira was carried out at Horticulture farm, SKNCOA, Jobner, Rajasthan, India. The study revealed that the application of Poultry manure @ 2.5 t/ha significantly increased the plant height (41.95 cm), Number of shoots per plant (12.71), chlorophyll content (1.11 mg/100g), days to 50% umbel initiation (134.50 days) , number of umbels per plant (17.30), number of seed per umbel (1177.35), diameter of umbel (16.71 cm), seed weight per plant (8.43 g), days to seed maturity (185.27 minimum days) and seed yield per hectare (6.24 q/ha). Similarly, the spray of ZnSO₄ @ 0.5% to the carrot crop significantly increased the plant height (40.60 cm), number of shoots per plant (12.49), chlorophyll content (1.07 mg/100g), days to 50% umbel initiation (133.51 days), number of umbels per plant (16.30), number of seed per umbel (1175.30), diameter of umbel (16.10 cm), seed weight per plant (8.39 g), days to seed maturity (184.12 days ) and seed yield per hectare (6.21 q/ha)

Extraction and analysis of back-sheet layer from waste silicon solar modules

Chitra Chitra, Dheeraj Sah, Parveen Saini, Sushil kumar — Fri, 16 Sep 2022 11:21:35 +0800

The back-sheet shields the solar panel from UV rays, moisture, dust, and other environmental factors. With the enormous growth of the solar industry year after year, the demand for recycling is also increasing rapidly. In the present study, the back-sheet layer was extracted from a waste crystalline silicon PV module by thermally heating the module at 130˚C temperature. Various characterization techniques, including Raman, FTIR, SEM-EDAX, XRD, and TGA, were used to examine extracted back-sheet layer properties for its reuse. The Raman and FTIR spectra of extracted back-sheet are quite similar to those of reference PET back-sheet, indicating that no significant changes in composition occurred during the extraction process. The extracted back-sheet has a composition of carbon and oxygen as witnessed from EDAX spectroscopy. The extracted back sheet maintained its semicrystalline behavior as that of the reference back sheet, observed by XRD spectroscopy. Thermogravimetric analysis revealed that the thermal stability of extracted back-sheet is up to 252˚C in the air environment and up to 315˚C in the inert environment. Thermal degradation of extracted back-sheet is a two-step process in an air environment observed by differential thermogravimetry. The observed properties of extracted back-sheet are comparable to those of commercially available back-sheet, and the same may be reused in solar and polymer industries after appropriate processing.

Fabrication of Pb₃O₄ and Fe₂O₃ nanoparticles and their application as the catalysts in thermal decomposition of ammonium perchlorate

Hossein Momenizadeh Pandas, Mostafa Fazli — Wed, 07 Sep 2022 14:38:24 +0800

Nanoparticles (NPs) of lead tetroxide (Pb₃O₄) with the spherical morphology were manufactured by the reaction of lead nitrate with sodium hydroxide, while the nanoparticles (NPs) of red iron oxide (Fe₂O₃) with similar morphology were fabricated by hydrothermal route in the presence of ferric chloride hexahydrate as the precursor. Evaluation of the chemical structure, the purity and the morphology of the manufactured Fe₂O₃ and Pb₃O₄ NPs was carried out by analysis via X-ray diffraction (XRD) as well as scanning electron microscope (SEM). The outcomes of XRD recognized establishment of the desired oxides, wherever the SEM images clearly exhibited the morphology of the manufactured Pb₃O₄and Fe₂O₃ as the spherical NPs with an average particle sizes of near to 40 and 46 nm, respectively. The catalytic effect of the metallic oxide NPs on the perfection of ammonium perchlorate (AP) thermal decomposing was established by testing their AP nano-composites via differential scanning calorimetric (DSC) together with thermogravimetric analysis (TG). Thermal behavior studies displayed that adding of 5% Fe₂O₃/Pb₃O₄ NPs (as the mixture) delivers a concerned catalytic effect during AP thermal decomposition. Additionally, thermal decomposition of AP could be amended by adding of 2% Pb₃O₄ NPs. Further comparison of the NPs catalytic effects was obtained by computing the values of activation energies (E) and thermodynamic parameters (i.e., ΔS^#, ΔH^# and ΔG^#) for their thermal decomposition by non-isothermal approaches.

Progress of hollow materials in diagnosis of COVID-19

Abid Hussain, Sonia Shabbir, Muhammad Faizan, Muhammad Ali Tajwar — Mon, 05 Sep 2022 09:43:34 +0800

Since the outbreak of COVID-19 in Wuhan, China, it has dramatically changed the global geopolitics, economics, and even society standard norms. The present world scenario is changed regarding business, traveling, and education. Rapid global dissemination and the high mortality rate of coronaviruses are the greatest challenges for drug developers. It will be moving forward toward the identification and treatment of emerging coronaviruses with the aid of nanotechnology. The COVID-19 pandemic raised the question of researchers’ capability to manage this dilemma in a short period. In the present review, we described how hallow material could be developed as a pro-drug that shows an excellent therapeutic effect. Hollow nanoparticles that exploration of antiviral or diagnostic agents against emerging coronaviruses. Hollow nanomaterials in vaccine development are essential because hollow nanocomposites are suitable for mimicking viral structures and antigen delivery. A biosensor that generates a signal from a transducer for comparing and analyzing biological conjugates such as cell receptors, antibodies, RNA, DNA, and nucleic acids. Different biosensors, such as graphene-based biosensors, nanoplasmonic sensor chips, nanomaterial biosensors, electrochemical biosensors, dual modality biosensors, and optical biosensors, have several advantages, characteristics, and a wide range of applications, most remarkably in medical treatment and are used for monitoring and diagnosis. This review focuses on modern experimental studies to identify intelligent and innovative bio/nanomaterials and matrices for developing targeted and controlled drug release systems, nanosensors and nanovaccines to combat pathogenic viruses.

Evaluation of an adsorption process for the treatment of leachates using biopolymers extracted from organic waste obtained from the poultry industry

Yeinner Tarazona, María Neftalí Rojas-Valencia, Juan Antonio Araiza-Aguilar — Thu, 02 Jun 2022 19:53:00 +0800

The adsorption capacity of three eggshell bioadsorbents was evaluated to remove contaminants from raw leachate. Optimal conditions for the removal of suspended solids, color, and organic compounds, as COD, were achieved by batch experiments with three levels of pH and absorbent concentrations. Kinetic studies and isotherms were developed to understand the behavior of COD removal by the bioadsorbents. The chemical and physical characterizations indicate the leachate used in the present study had characteristics between mature and intermediate leachates. The optimal adsorption conditions were pH 2.0 and 1.0 gram (0.5 g/L) of adsorbent. Adsorbent M showed the best adsorption capacities, removing 99.06% (1446 NTU) of turbidity, 86.25% (4140 UPt-Co) of color and 54.56% of COD (1530mg/L). The data obtained through the kinetic and isothermal tests were better fitted to the pseudo first order and Langmuir models, with an equilibrium adsorption capacity (Qe) of 139 mg of COD/g of adsorbent and a specific speed of 1.51 min^-1.

Textile solid waste in product development studies

Faheem Uddin, Komal Umer, Syeda Tehniyat Anjum — Mon, 28 Mar 2022 16:26:04 +0800

Textile solid waste disposal and utilization is currently an important concern worldwide. Fashion and traditional articles of textiles are sourcing the solid textile waste generation. An increasing population and consumption of fiber and textile articles emphasize the development studies for the re-use of solid textile waste. Production of textiles is accompanied by the release of volatile emission and effluent during processing, and disposal of fibrous articles are producing solid waste. The hazardous waste generated from the textile can be seen as pre- consumer solid waste (fiber, yarn, and fabric pieces), processing waste (volatiles, chemicals and effluent release during the process), and post- consumer waste (textile fabric, yarn, apparel, home textiles, technical textiles, etc.) dispose to environment following the service life. Therefore, re-using the fiber and textile articles can significantly reduce undesired effects to environment. Designing the products using solid textile waste can be a useful source for reducing the environmental hazard. This study describes the re-use of various fiber and textiles, though the case studies, particularly denim fabric, in designing the products for home decoration.

Neuron-like tubule extension of giant polymer vesicles

Eri Yoshida — Fri, 26 Nov 2021 11:38:58 +0800

Giant polymer vesicles consisting of amphiphilic diblock copolymers are helpful as artificial biomembrane models based on many similarities in their size, structure, morphological transformation, membrane permeability, etc. This paper describes the creation of neuron-like tubule extension employing the polymer vesicles. The polymerization-induced self-assembly was performed in the presence of micron-sized spherical vesicles consisting of poly(methacrylic acid)-block-poly(methyl methacrylate-random-methacrylic acid), PMAA-b-P(MMA-r-MAA), through the photo nitroxide-mediated controlled/living radical polymerization (photo-NMP) using 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxyl (MTEMPO) as the mediator. The photo-NMP of methyl methacrylate (MMA) and methacrylic acid (MAA) was carried out in an aqueous methanol solution (CH₃OH/H₂O = 3/1 v/v) using poly(methacrylic acid) (PMAA) end-capped with MTEMPO and the spherical vesicles of PMAA₁₄₁-b-P(MMA_0.831-r-MAA_0.169)₃₆₈ with an 11.7-mm diameter. The vesicles projected many processes on their surface during the early stage of the polymerization. As the polymerization progressed, only one or two of the processes extended to thick tubules, accompanied by the slow growth of thin tubules. Further progress of the polymerization elongated the thick tubules and caused branching of the tubules. The tubules had a vesicular structure because cup-like vesicles joined in line were formed during the initial stage of the extension. The polymerization livingness supported the tubule extension based on a linear increase in the molecular weight of the component copolymer and a negligible change in the molecular weight distribution versus the monomer conversion. The spherical vesicles were similar to the neurons in the tubule extension for the initial projection, followed by the elongation and branching. This similarity implies that the neurite extension in the neurons is related to the inherent property of the bilayer membrane.

An ideal fatty acid composition for human health: Hemp (Cannabis sativa L.) seed

Ezgi Aytaç — Wed, 21 Jul 2021 14:16:50 +0800

The objective of this study was to show and crosscheck the seed yield and oil composition of three different seeds growing in different regions of Turkey. Extraction with n-hexane solvent indicated that there were differences in terms of oil yield between the regions. The average oil yield was 33.8% and 33.0% seed-I, 35.7% seed-II (Region-a) and 32.6% seed-III (Region-b) oil yields were obtained. The highest fatty acid content of hemp was found as: linoleic acid (average 55.24%) followed by oleic acid (average 17.20%) and α-linolenic acid (average 16.02%). Crude ash, total dry matter and crude protein analyzes were also performed. It was observed that the hemp seed oil yield was dependent on the extraction whereas extraction had no influence on the fatty acid content. Comparison of the seed oil yield with the other studies indicated that geographical region as well as the extraction method may affect the seed oil yield.