Enhanced Electrochemical Performance of Biomass Porous Carbon Adsorption Congo Red

Biomass porous carbon has received widespread attention due to its application as electrode material for supercapacitors and adsorbent for difficult-to-degrade organic dyes. In this paper, biomass porous carbon KGL is prepared using ginkgo leaves as the precursor and KOH as the activator. Capitalizing on the adsorption property of porous carbon, an azo dye Congo red (CR) is confined into the nanopores of KGL to fabricate the KGL/CR electrode. The result suggests that KGL has good adsorption performance for organic dye and KGL/CR has excellent capacitance performance. When the CR concentration is 500 mg L-1, the adsorption capacity of KGL is 495 mg g-1. KGL/CR-500 displays elevated specific capacitance of 393 F g-1 at 1 A g-1 and excellent rate performance (76.3% capacitance retention at 10 A g-1). The capacitance retention after 10000 cycles maintains 99%. The symmetric supercapacitor has power density of 699.8 W kg-1 at an energy density of 16.4 Wh kg-1 and can power a light emitting diodes (LED). Our work provides the information that one is the treatment of organic dye wastewater, the other is development of electrochemical energy-storage materials, and may be expanded to the resource-utilization of other versatile effluent containing the redox groups.

Assessment of Heavy Metals in Agricultural Soils and Plant (Vernonia amygdalina Delile) in Port Harcourt Metropolis, Nigeria

This study assessed the concentration of heavy metal, such as lead (Pb), cadmium (Cd), Chromium (Cr), iron (Fe), Nickel (Ni), and Silver (Ag), in Vernonia amygdalina Delile and agricultural soils of three university farms located in Port Harcourt, Nigeria. The soils and plants were taken randomly to form composite samples and analyzed for heavy metals by the use of atomic absorption spectroscopy (AAS) and X-ray fluorescence (XRF). The study stations were agricultural soils and Vernonia amygdalina Delile from the Ignatius Ajuru University of Education (I), River State University (R) and University of Port Harcourt (U). The soil samples recorded mean concentration ranges for Fe as 19.71 ± 1.77 (I)–27.24 ± 3.56 mg/kg (R) in soils and 12.95 ± 1.68 (R)–18.18 ± 2.02 mg/kg (U) for the bitter leaf samples. The mean range for Pb concentration in the soil and bitter leaf were 4.35 ± 0.87–6.80 ± 0.86 mg/kg and 0.24 ± 0.64–2.19 ± 0.74 mg/kg, while Cd concentration in the soil and bitter leaf were 0.46 ± 0.28–1.42 ± 0.40 mg/kg and 0.17 ± 0.22–0.42 ± 0.08 mg/kg, respectively. The respective mean ranges for Cr concentration in the soil and bitter leaf were 5.91 ± 1.14–8.77 ± 0.88 mg/kg and 4.04 ± 0.64–5.92 ± 0.69 mg/kg, while Ni in soil and bitter leaf were 0.54 ± 3.38–10.26 ± 3.50 mg/kg and 0.042 ± 1.42–3.30 ± 0.88 mg/kg, while Ag was negligible. Heavy metal levels in soils and Vernonia amygdalina followed the order Fe > Cr > Pb > Ni > Cd and Fe > Cr > Ni > Pb > Cd, respectively, and were lower than WHO/FAO and EPA, except Cd, which was higher in soil and in Vernonia amygdalina. The ecological risk factor (ErF) was comparatively lower in soils than in the plant, while pollution load index (PLI) showed high heavy metal retention capacities in Vernonia amygdalina due to more anthropogenic influences. The metal transfer factor (TF) was highest in Fe, followed by Cr > Cd > Ni > Pb, while Pb had the highest chances of cancer risks from the incremental lifetime cancer risk (ILCR), especially in both soil and plant (mean ILCR, 2.07 × 10−2 and 2.45 × 10−3), while Cd had the least (mean ILCR, 9.64 × 10−5 and 3.36 × 10−5). Anthropogenic activities must be regulated and monitored by government relevant agencies to reduce heavy metal inputs into soils and avoid excessive accruals in food chain.

Current iodine status in Japan: A cross-sectional nationwide survey of schoolchildren, 2014–2019

Context Japan has been regarded as a long-standing iodine sufficient country without iodine fortification; however, data on nationwide iodine status is lacking. Objective This study aimed to characterize the iodine status in Japan. Methods From 2014 through 2019 a nationwide school-based survey was conducted across all districts in Japan. Urinary iodine concentration (UIC), creatinine (Cr) concentration and anthropometry were assessed in healthy school-aged children (SAC) aged 6 to 12 years. Their iodine status is regarded as generally representative of the nation's iodine status. Results A total of 32,025 children participated. The overall median UIC was 269 μg/L which was within the WHO’s adequacy range. There was a regional difference in UIC values within 14 regions, and the lowest and highest median UIC were found in Tanegashima Island (209 μg/L) and Nakashibetsu, Hokkaido (1,071 μg/L), respectively. The median UIC ≥ 300 μg/L was observed in 12 out of 46 regions. By using estimated 24-h urinary iodine excretion (UIE), the prevalence of SAC exceeding the upper tolerable limit of iodine for Japanese children was from 5.2 to 13.7%. The UIC values did not change with age, BSA and BMI percentile, while the Cr concentration simultaneously increased suggesting the effect of urinary creatinine on UI/Cr and estimated 24-h UIE values. Conclusions The iodine intake of Japanese people is adequate, but in some areas it is excessive. The incidence and prevalence of thyroid disorders associated with iodine intake should be obtained especially in the areas where high amounts of iodine are consumed.

Statistical Interpretation and Profiling the Leaching Characteristic of Chromium in the Basic Chrome Sulphate (BCS) Sludge Dumping at Village Khanchandpur-Rania, District Kanpur Dehat, Uttar Pradesh (India)

Without immobilized hazardous waste contaminates soil and groundwater, which can further bio-accumulates and poses serious negative health impact on flora as well as fauna. The present investigation has been conducted to study of leaching behavior of chromium species in immobilized hazardous waste containing Basic Chrome Sulphate (BCS) dumped at dumping site Khanchandpur Kharanja, Rania, Kanpur Dehat district of Uttar Pradesh, India. Results indicated that the pH of sludge ranged from 10.16–11.90 while EC ranged from 840-16160 dSm-1 in a different layer of the dumpsite and significantly varies on increasing depth. A similar trend was also observed in TDS contents which strongly justified the leaching of salts in lower depth. Total Cr concentration (25029.94 mg kg-1) was observed in the top layer which was significantly increased on increasing depth i.e., 36102.0 mg kg-1 and 42811.77 mg kg-1 while TCLP based concentration ( 216.44 mg kg-1 in top layer) was significantly increased on increasing depth i.e., 406.25 mg kg-1 and 517.60 mg kg-1. A similar trend was also observed in total and TCLP hexavalent and trivalent (Cr6+ and Cr3+) chromium concentration. Hierarchical Cluster Analysis is separated all sample based on depth into three different cluster based on dissimilarity. A significant correlation was observed with TCLP Cr6+ in TCLP Cr3+, EC, and TDS at 0.01 levels while EC, TDS, total Cr6+, and TCLP Cr were significant correlated with TCLP Cr3+. The leaching behavior of Cr species was higher as well as increasing of depth in the dumping site.

Application of Nano Bio-clay Composite in a Scaling-up Study for Wastewater Treatment

A scaling-up study integrating experimental and field experiments was managed to explore the most appropriate catalysis method to assist industries in getting rid of the Congo Red (CR) dye from industrial wastewater. The adsorption potential of kaolinite (K) modified by Ulva Lactuca (UL) was evaluated to eliminate CR dye from aqueous solutions. The novel kaolinite/alga nanocomposite (KUL) was synthesized following steps of the wet impregnation method and then subjected to characterization using different techniques. The newly reported KUL nanocomposite shows a significant increase in adsorption ability higher than that of K and UL. To research different experimental factors' effects, batch experiments were evaluated, and each of the kinetics/isotherms of CR adsorption were explored either. The CR removal% is clearly affected by catalyst dose, working temperature, and pH value with high percentage. The best temperature for CR adsorption onto KUL is 400C at pH>7. CR adsorption on KUL following the first-order diffusion model, while K and UL appeared to follow two different kinetic adsorption models depending on the CR concentration. Moreover, the field tests (scaling-up experiments) revealed optimistic results with 91% efficiency for KUL nano-adsorbents in eliminating mixed dyes from industrial wastewater, which means the foundation of novel environmentally benign nano-adsorbents to help in industrial wastewater recycling.

Modeling the marine chromium cycle: new constraints on global-scale processes

Chromium (Cr) and its isotopes hold great promise as a tracer of past oxygenation and marine biological activity due to the contrasted chemical properties of its two main oxidation states, Cr(III) and Cr(VI), and the associated isotope fractionation during redox transformations. However, to date the marine Cr cycle remains poorly constrained due to insufficient knowledge about sources and sinks and the influence of biological activity on redox reactions. We therefore implemented the two oxidation states of Cr in the Bern3D Earth system model of intermediate complexity in order to gain an improved understanding on the mechanisms that modulate the spatial distribution of Cr in the ocean. Due to the computational efficiency of the Bern3D model we are able to explore and constrain the range of a wide array of parameters. Our model simulates vertical, meridional, and inter-basin Cr concentration gradients in good agreement with observations. We find a mean ocean residence time of Cr between 5 and 8 kyr and a benthic flux, emanating from sediment surfaces, of 0.1–0.2 nmol cm−2 yr−1, both in the range of previous estimates. We further explore the origin of regional model–data mismatches through a number of sensitivity experiments. These indicate that the benthic Cr flux may be substantially lower in the Arctic than elsewhere. In addition, we find that a refined representation of oxygen minimum zones and their potential to reduce Cr yield Cr(III) concentrations and Cr removal rates in these regions in much improved agreement with observational data. Yet, further research is required to better understand the processes that govern these critical regions for Cr cycling.

Concentration of Vehicular and Generators Soot in Lafia Metropolis, Nasarawa State, Nigeria

The concentrations of Pb, Cd, Cr, Al and Fe in Heavy Duty Trucks (HDT), Power Generating Plants (PGP), Motor Vehicles (MV) and Small Generator (SG) Soot derived from the College of Agriculture, Bukan Sidi and Mararaba Akunza in Lafia City, Nigeria, were assessed for the level of contamination using Atomic Absorption Spectrophotometer (AAS). The results indicated that the ranges of heavy metal concentrations in soot (mg/kg) were: Pb (0.0911±0.001 to 0.069±0.008) for the HDTs, (0.775±0.008 to 0.002±0.000) for the PGPs, (0.456±0.000 to 0.091±0.000) for the MVs and (0.837±0.000 to 0.027±0.000) for the SGs. The concentrations of Cd and Cr in the HDTs and PGPs were below the detection limits of the AAS. More so, Cd and Cr in MVs were below the detection limits of the AAS except for one of the MVs which gave a highly objectionable Cr concentration of 4.336±0.004 above WHO permissible limits for emissions into air and water. Al concentrations across the soot samples ranges from (0.126±0.002 to 0.093±0.001) for HDT, (0.170±0.001 to 0.097±0.000) for PGPs, (0.150±0.000 to 0.057±0.001) for MVs; and (1.348±0.000 to 0.518±0.000) for SGs. Iron concentrations ranges from (65.885±0.006 to 27.834±0.009) for HDTs, (62.663±0.004 to 11.422±0.019) for PGPs, (52.448±0.003 to 2.418±0.001) for MV, and (129.433±0.008 to 9.129±0.002) for the SGs. The results revealed that the concentration of Pb, Al and Fe in the HDTs, PGPs, MVs and SGs are above the WHO permissible limits for emissions into air and water. Cd, Cr, Al and Fe concentrations were higher in concentrations in SGs. The presence of heavy metals in the sampled soot portends their transfer to the food chain, especially as crop and vegetable cultivation in and around Lafia city.

Heavy metals immobilization and improvement in maize (Zea mays L.) growth amended with biochar and compost

Soil with heavy metals contamination, mainly lead (Pb), cadmium (Cd), and chromium (Cr) is a progressively worldwide alarming environmental problem. Recently, biochar has been used as a soil amendment to remediate contaminated soils, but little work has been done to compare with other organic amendments like compost. We investigated biochar and compost's comparative effect on Pb, Cd, and Cr immobilization in soil, photosynthesis, and growth of maize plants. Ten kg soil was placed in pots and were spiked with Pb, Cd, and Cr at concentrations 20, 10, 20 mg kg−1. The biochar and compost treatments included 0, 0.5, 1, 2, and 4% were separately applied to the soil. The crop from pots was harvested after 60 days. The results show that the highest reduction of AB-DTPA extractable Pb, Cd, and Cr in soil was 79%, 61% and 78% with 4% biochar, followed by 61%, 43% and 60% with 4% compost compared to the control, respectively. Similarly, the highest reduction in shoot Pb, Cd, and Cr concentration was 71%, 63% and 78%with 4% biochar, followed by 50%, 50% and 71% with 4% compost than the control, respectively. The maximum increase in shoot and dry root weight, total chlorophyll contents, and gas exchange characteristics were recorded with 4% biochar, followed by 4% compost than the control. The maximum increase in soil organic matter and total nitrogen (N) was recorded at 4% biochar application while available phosphorus and potassium in the soil at 4% compost application. It is concluded that both biochar and compost decreased heavy metals availability in the soil, reducing toxicity in the plant. However, biochar was most effective in reducing heavy metals content in soil and plant compared to compost. In the future, more low-cost, eco-friendly soil remediation methods should be developed for better soil health and plant productivity.

A study on chromium accumulation in Labeo rohita in the river Yamuna ecosystem in Mathura-Agra region in Uttar Pradesh, India

The present study revealed the chromium toxicity and its health measures in L. rohita from the Yamuna river at Mathura- Agra region. Samples were taken in triplicate from both sites i.e. Vrindavan (Bihar ghat) and Agra (Renuka Ghat). The study was carried out on Four different organs (i.e. gills, muscles, liver, and kidney) of the fish sample. The sampling was done from Oct 2018 to January 2020. Chromium concentration in different organs of the fish was analyzed by Atomic absorption spectrophotometer(AAS). The average Cr concentration in gills was highest (9.64 mg/l) at the Mathura site followed byAgra sites (7.78 mg/l) for the month of April 2019. The concentration of Cr was highest in samples taken in the month of April 2019 and it was lowest in October 2018. The significantly high Cr concentration values were observed in the Mathura region than the Agra region for both seasons. In all samples, Cr concentration was above the standards stated by WHO except in the Kidney. In the present study, the bioaccumulation factor showed the chromium concentration in the tissues followed the order of gill > liver > muscle > kidney. HPI, MQI, and Pearson’s correlation coefficient analysis were also done in which HPI was observed very high and there was a positive correlation between all the samples. Keywords: Chromium, BCF, HPI, MQI, AAS, Fish Organs

Synthesis of Gold Nanoparticles Using Tannin-Rich Extract and Coating onto Cotton Textiles for Catalytic Degradation of Congo Red

Gold nanoparticles (AuNPs) were synthesized under ambient conditions from chloroauric acid in aqueous solution at pH 4. Tannin-rich extract from Xylocarpus granatum bark was used as both reducing and capping agent, rapidly converting Au (I) salt to AuNPs. Transmission electron microscopy showed the as-prepared AuNPs to be predominantly spherical, with an average diameter of 17 nm. The AuNPs were tested for catalytic reduction of Congo red (CR), a carcinogenic azo dye, in aqueous sodium borohydride solution. Cotton samples were coated with the AuNPs, taking on a reddish-purple color. The samples showed significantly reduced tearing strength after coating, though tensile strength was unaffected. UV-visible spectroscopy was used to determine the dye concentration in the water. CR degradation was observed only when AuNPs were present, and the efficiency of degradation was strongly linked to the AuNP loading. The AuNP-coated fabrics left only a 4.7% CR concentration in the solution after 24 h and therefore promise as a heterogeneous catalyst for degradation of CR in aqueous solution.