Atomic Adsorption Spectrophotometer Research Articles

Reduction of Metal Density of Iron (Fe) and Natrium Minerals (Na) in Boring Water Using Rubber Fruit Sheets Active Archoic

Activated carbon is a highly popular adsorbent for the absorption of metal ions. Lignocellulosic materials can be used to produce activated carbon, which is both renewable and abundant, as well as being cost-effective. The objective of this research is to investigate the reduction of iron (Fe) and sodium (Na) levels in the artesian well by utilizing activated carbon made from rubber shells. The materials utilized include rubber shells, a solution containing 10% H3PO4 (phosphoric acid), water from an artesian well, and distilled water (aquadest). The carbonization process was conducted at 300º C for 1 h, using an adsorbent size of 120 mesh. In addition, chemical activation was performed using a 10% H3PO4 solution for 24 h, followed by physical activation through heating in a furnace at a temperature of 500ºC for 1 hour. The acquired activated carbon is utilized for the absorption of Fe and Na. The activated carbon was characterized using X-ray diffraction (XRD), and the concentration of Fe and Na minerals was determined using an Atomic Adsorption Spectrophotometer (AAS). The results indicated a reduction of 97.9% in the concentration of iron (Fe) and a decrease of 90.01% in sodium (Na) levels.

Elimination of Chromium (Vl) from Industrial Effluent through the Utilization of Water Hyacinth weed

Biosorption is a physico-chemical binding of a substance to biological material. Water hyacinth has been successfully utilized for the removal of chromium (VI) from waste water samples. The plants were divided in to two part (i) root (ii) foliage. Each part was dried at 750 C for 48 hours and then its weighed was taken. The tissue samples weight then ash in the muffle-furnace at 3500 C for 5 hours. Ash samples were digested with acids (HNO3, HCl) and diluted with 100 ml of distilled water. The detection of chromium (VI) carried out by Atomic Adsorption Spectrophotometer (AAS). This method of removing chromium from water is cost-effective, eco-friendly, and has been shown to be effective in laboratory studies.

Efficient Copper Adsorption from Aqueous Solution by Dictyuchus sterile Pellets

A common heavy metal pollutant of water resources, copper (II), can cause serious health problems or even death. Over the past few years, several filamentous fungi strains have been isolated, identified, and tested for their ability to bio-adsorb heavy metals for potential use in the bio-remediation of copper from wastewater. In this study, variables, including the dosage of fungal pellets, temperature, pH, time, initial copper concentration, and agitation rate, were assessed to select the best conditions for the adsorption of copper by Dictyuchus sterile pellets. To identify the active groups responsible for metal adsorption, microscopic observations were made using a light microscope and scanning electron microscope. The copper adsorbent was then analyzed before and after adsorption using an atomic adsorption spectrophotometer and Fourier transform infrared spectroscopy. The ideal adsorption conditions were: fungal pellets with a wet weight of 1 g.L-1 at a temperature of 25°C, pH 5.5, the initial copper concentration of 100 ppm, and shaking at a speed of about 250 rpm for 72 h to achieve a removal efficiency rate of 95%. Copper adsorbed with the biomass of the fungal pellets was 57 mg.g-1. The use of fungal pellets would be a method that can be used to increase the surface area of adsorption and also is thought to be one of the most cost-effective ways to remove trace metals from polluted water.

Apple peels as a potential adsorbent for removal of Cu and Cr from wastewater

Abstract Solid waste management (SWM) is one of the biggest concerns of society and agricultural waste is generated in vast amounts. In this study removal of Cu and Cr from wastewater using chemically modified apple peels was studied by following batch sorption experiments. Effects of metal concentration, adsorbent dose, pH, temperature and contact duration on the adsorption of Cu & Cr were investigated by using atomic adsorption spectrophotometer (AAS). SEM & EDX analysis of the adsorbents were recorded to study the morphology of the prepared adsorbents. Qmax value of apple peels is 25 for Cr and 22 for Cu, while for apple peel charcoal it is 33 for Cr and 47 for Cu, for treated apple peels Qmax is 50 for Cr and 52 for Cu adsorption. The data was processed using pseudo first, second order kinetic and intraparticle diffusion. Results depicted that the calculated adsorption capacities (qecal) were found to be close to the experimental values (qecal) by following pseudo-second-order kinetics. The applicability of the Langmuir and Freundlich adsorption isotherms was tested. Results showed that the Langmuir model is best fitted on adsorption data because regression factor R2 values are good for the Langmuir model.

Ecological pollution and health risk monitoring assessment of polycyclic aromatic hydrocarbons and heavy metals in surface water, southeastern Nigeria.

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are predominant pollutants linked with anthropogenic activities across a host of environmental mediums. The level of pollution, ecological and health risk were assessed in surface water from Ekulu in Enugu metropolis, Nigeria for 17 PAHs and selected HMs (As, Cd, Cr, Cu, Pb, Ni, Zn) components. PAHs and HMs were determined using a gas chromatography-flame ionization detector (GC-FID) and atomic adsorption spectrophotometer (AAS). The total PAHs in station A (3.17mg/l), B (1.51mg/l), and C (1.83mg/l) were due to high molecular weight (HMW) PAHs than low molecular weight (HMW) PAHs. HMs contents were within USEPA and WHO minimum contamination levels (MCL) except Cr and Pb. The molecular diagnostics of PAHs showed that incomplete combustion of carbonaceous compounds was dominant, while petrogenic was insignificant across all samples. The ecological indices of PAHs and HMs varied from medium to high pollution due to anthropogenic activities that pose a threat to the ecosystem. The non-carcinogenic models showed that hazard index (HI) ranged from PAHs (0.027 - 0.083) and HMs (0.0067 - 0.087) which is less than unity implying no adverse health issues. The lifetime cancer risk (LCR) for PAHs (4.21×10-4 - 9.61×10-4) and HMs (1.72×10-5 - 3.98×10-5) suggested significant cancer risk is possible over some time for a population of 1 in 10,000 and 100,000 for both PAHs and HMs exposure for 70 years. Therefore, there is an urgent need for proper pollution control and mitigation plan to preserve both age groups from being continuously exposed to anthropogenic activities in the Ekulu River and further study should be carried out to monitor the available toxicants.

Assessment of the dietary pattern and serum zinc concentrations of adults in Umuahia North Local Government Area, Abia State

Dietary pattern is a parameter that assesses the general profile of food and nutrient consumption which is characterized on the basis of the usual eating habits. This study was conducted to assess the dietary pattern and serum zinc concentrations of adults in Umuahia North Local Government Area, Abia State. To achieve this, a cross-sectional analytical study design was conducted on a designed questionnaire distributed amongst 252 respondents to collate data on their socio-demographic characteristics on age, sex, marital status, religion, occupation, and educational levels. Food Frequency Questionnaire (FFQ) was also carried out to assess adults’ dietary patterns daily, weekly, sometimes and none, on some foods such as cereals, vegetables, legumes, milk & dairy, meat, fish & seafood, eggs, roots, and tubers. Serum zinc was conducted on 50 volunteered adults from the study area. Serum zinc levels present in the collected blood samples were analyzed with the aid of an Atomic Adsorption Spectrophotometer (AAS). Data obtained was analyzed with the aid of SPSS software on mean, standard deviation, t-test, and ANOVA for the hypothesis. Serum zinc deficiency was defined as a zinc level of less than 46 ug/dl from a reference book. The mean concentrations of serum zinc of healthy adults conducted were recorded as male 49.566 ± 19.384, female 24.017±6.999, 38.025±24.862 (18-25years ), 37.305±18.263 (26-40years) and 39.294±19.446 (41-55years) respectively. The results revealed that serum zinc concentrations in the participating healthy adults were within the reference level of 46 ug/dl, and also statistically significant at a p-value of 0.01 for the alternate hypothesis. Also, the relationship test of association between dietary pattern and serum zinc concentration is statistically significant as their p-value was less than 0.05 (0.027). Also, the tests confer with the alternate hypothesis that the association between dietary pattern and serum zinc concentration of adults in Umuahia North LGA is statistically significant. This study, therefore, recommends that studies should be carried out in other areas where symptoms of zinc deficiency are evident.

Equilibrium studies for the removal of manganese (Mn) from aqueous solution using natural zeolite from West Java, Indonesia

Manganese (Mn) is one of the heavy metals found in industrial wastewater, such as acid mine drainage, which has caused serious environmental problems worldwide. This equilibrium study was carried out to determine the maximum capacity of natural zeolite towards manganese removal from made aqueous solution as affected by zeolite quantity, particle size, activation temperature, and initial pH of the solution. The natural zeolites obtained from Tasikmalaya, West Java, Indonesia, were crushed and filtered into three groups of diameters: <0.5, 1-2, and 2-4 mm. Each group was divided into two sub-groups, one sub-group was heated in a muffle furnace at 250 <sup>o</sup>C for two hours, and the other sub-group was left at room temperature (25 <sup>o</sup>C). This experiment consisted of two sections. Section one was physical and chemical characterizations of the natural zeolite, using Scanning Electron Microscopy (SEM), X-Ray Diffraction, and X-Ray Fluorescence techniques. The second section was equilibrium studies using two series of 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, and 5 g of natural zeolites of each sub-groups, then respectively added with 50 mL of a solution containing 50 ppm Mn having pH of 5.5 and 7.0. All suspensions were shaken for 24 h and filtered. The filtrates were red for total dissolved Mn using Atomic Adsorption Spectrophotometer (AAS). Freundlich and Langmuir isothermic models were fitted to the collected data to describe the adsorptive behaviour of Mn toward natural zeolites. Data showed that 0.5 g of natural zeolite had removed the remarkably highest Mn from the solution, regardless of the size of the particles, thermal treatment, and initial solution pH. The smallest size of zeolite particle and higher initial solution pH tended to increase the adsorptive capacity of the natural zeolite toward Mn. The Freundlich isothermic model fitted better to Mn adsorption behaviour than the Langmuir model.

The Effectiveness of Active Carbon Adsorbent of Cassava Peel (Manihot Esculenta Cranzts) in Reduce Level of Chromium Metal in Tannery Liquid Waste

This study aims to determine the characteristics, the effect of mass variation, the percentage of adsorption effectiveness of cassava peel activated carbon activated with 0.5 M HCl and activated with 0.5 M H2SO4 on the adsorption of Cr metal in leather tanning wastewater and its morphology. The subject of this research is the adsorbent of cassava peel before it is asctivated, activated by chloric acid 0,5 M, and activated by sulfuric acid 0,5 M. meanwhile the object of this research is the effectiviness of cassava peel adsorbeny in reduscing chromium metal content in tannery liquid waste. Cassava pell was carbonized at 500 oC for 1 hour. The cassava peel carbon was characterized according to SNI 06-3730-1995. The adsorption process is performed by batch method. Analysis was performed by Atomic Adsorption Spectrophotometer, PSA, and SEM-EDX. The result of the characterization of cassava peel carbon showed that the moisture content, ash content, adsorption capacity of I2 met SNI, meanwhile the carbon contenr and volatile matter conten did not met SNI. The adsorption efficiency of kromium metal is 95.97% for carbon before activated, 95.33% for carbon activated by chloroc acid, and 96.65% for carbon activated by sulfuric acid. The result of PSA size of cassava peel adsorbent before activated by chloric acid and sulfuric acid were 34.484 µm, 42.504 µm, and 37.059 µm respectively. Cassave peel adsorbent has a Langmuir adsorption type. The SEM-EDX result showed that the adsorbent from cassava peel had a dissimiliar pore shape

Health risk of some metals in maize grains cultivated close to Gosa and Gwagwalada solid waste dumpsites

Maize is a vital nutritional cereal for the infants, young children and adults. The environment which they are cultivated in Africa could expose to metal accumulations from soils, thereby posing health risks to the consumers. The objectives of this study were determine metal accumulations in maize grains (Zea mays L.) cultivated close to Gosa and Gwagwalada solid waste dumpsites and their health risks via consumption. A total of 36 soil samples (12 each from dumpsite soil, farmland soil and maize grains) were collected and analyzed for some metals [cadmium (Cd), lead (Pb), zinc (Zn), cobalt (Co), copper (Cu), chromium (Cr), nickel (Ni) and mercury (Hg)] using standard atomic adsorption spectrophotometer. The transfer factors and metal health risks in adults (60 kg; 22-48.9 years), young children (35 kg; 6-15 years) and infants (15 kg; 1-6 years) were evaluated using mathematical models. The ranges of metal (mg/kg) detected were 10114.00 to 0.52, 10.45 to 0.001 and 13.62 to 0.001 for dumpsite, farmland and maize grains, respectively. Though, within FAO/WHO and EU safe limits, Zn was significantly (p<0.05) highest in both locations, while Cd, Cr and Hg (0.001 mg/kg) were the least. Only Zn had transfer factor value below 0.5, which indicates possibilities of anthropogenic elevations. The estimated daily intake from consumption of maize grains (57 g) were generally high for Zn and low for Ni, Cd, and Hg in exposed individuals. The hazard index was below 1, which indicates no significant non-carcinogenic risks in exposed populations. The incremental lifetime cancer risks was below 10-6 and this suggest potential lifetime cancer risks in the order infants ? children ? adults. This study concluded that daily consumption of maize cultivated closed to dumpsites poses potential lifetime cancer concern and thus maize farming around dumpsites needs to be discouraged for safety reasons.

Flame Atomic Adsorption Spectrophotometer (FAAS) to Assess the Concentration of Heavy Metals (Pb, Cd, Cr, and Zn) in Porites Coral from Ambon Bay, Indonesia

The concentration of metals in coral represents environmental changes, monsoonal variation, and human disturbance. Metals in coral were used as a proxy to evaluate the response of coastal areas to climatic and human stresses. In this study, several metals including lead (Pb), cadmium (Cd), chromium (Cr) and zinc (Zn) in Porites coral taken from Ambon Bay, Ambon Island, Indonesia, were investigated. The history of metals transient in the most populated island in Maluku Province is documented here from measurements of metals concentration from monthly-banded coral that grew in coastal seawater from 2001 to 2009. The concentration of heavy metals in coral samples was measured using Flame Atomic Adsorption Spectrophotometry (FAAS) method. The results showed metals bioaccumulation (average ± STD) were following decreasing order: Pb (0.96 ± 1.58 μg/g) > Cr (0.15 ± 0.34 μg/g)> Zn (0.11 ± 0.26 μg/g) > Cd (0.007 ± 0.016 μg/g). Moreover, all metals content in the coral showed a remarkable rose from 2001 to 2009 and showed relatively high concentrations during the southeast monsoon for Pb and Cd. Based on the statistical analysis, all metals in Ambon Bay coral were impacted by terrestrial input. In addition, Pb and Cd were also impacted by natural processes that may be associated with their biogeochemical cycle and monsoonal variation.

Rational synthesis and characterization of highly water stable MOF@GO composite for efficient removal of mercury (Hg2+) from water

The present study is aimed at adsorptive removal of Mercury (Hg2+) using highly functionalized nanomaterials based on Graphene Oxide Zeolitic Imidazolate Framework composite (ZIF-67@GO). Solvothermal methodology was used to synthesize ZIF-67@GO composite. Synthesized compounds were confirmed by FTIR, SEM, PXRD and EDX analysis. The as-prepared ZIF-67@GO was tested as efficient adsorbent for effective removal of Mercury (Hg2+) from aquatic environment. The atomic adsorption spectrophotometer was used to monitor the process of adsorption of Hg+2 on ZIF-67@GO. From the adsorption data, the maximum removal efficiency achieved was 91.1% using 10 mg amount of composite for 50 mL using 20 ppm Mercury (Hg2+) solution. Different parameters like pH, contact time, concentration, adsorption kinetics and isotherm were also examined to explore adsorption process. Adsorption data fitted well for Freundlich Model having R2 value of 0.9925 than Langmuir Isotherm with R2 value of 0.9238. Kinetics were rapid and excellently described via 2nd order model with R2 = 0.99946 than 1st order model with R2 value of 0.8836. Freundlich and pseudo 2nd order models validated that multilayer chemisorption occurs during adsorption process due to the presence of highly functionalized sites on ZIF-67@GO composite. The synthesized composite material has shown excellent reusability. Thus, water stable ZIF-67@GO composites can efficiently be used for Mercury (Hg2+) confiscation from water.

Evaluation of electro-assisted phytoremediation (EAPR) system for heavy metal removal from synthetic leachate using Pistia stratiotes

The highest waste generated in Malaysia is composed of municipal solid waste, which is mainly managed by landfilling. Heavy metals in leachate generated from landfill could have caused hazardous effects to human and environment. EAPR has been increasingly applied to treat soil and wastewater. This technique serves as a potential tool for remediation of real leachate. Metals (Mn, Cd, Fe, Ni, Pb, Zn) uptake by Pistia stratiotes were evaluated via flame atomic adsorption spectrophotometer. Pb and Fe could be the elements that were more efficiently removed by P. stratiotes in the EAPR system. The removal efficiency was 59.86 ± 9.98 and 56.56 ± 18.08% for Pb and Fe, respectively. EAPR significantly reduced the BOD (9.37 ± 2.36 mg/L), color (120.00 ± 5.77 PtCo), and turbidity (25.50 ± 11.96 NTU) of synthetic leachate. An obvious accumulation of heavy metals was observed at roots based on BCF and TF values. BCF values of Pb (18,999.06 ± 8,321.76) and Fe (16,090.81 ± 5,844.36) in the EAPR system were more than 103, which indicates that P. stratiotes is a hyperaccumulator. Further study on the upregulated genes is needed to comprehend the molecular basis of heavy metal stress tolerance.

Komparasi Kandungan Timbal (Pb) Kertas Bekas Mengandung Tinta Pasca Aplikasi Cairan Rumen Sapi Berdasarkan Lama Inkubasi

The addition of cow rumen fluid to waste containing cellulose can help decompose the cellulose contained in it through the composting process. Organic waste and paper waste containing ink are wastes that contain cellulose. However, the waste paper containing ink contains Lead (Pb) which is used as a color binding agent in the ink. In the composting process, in addition to the degradation process of organic components in paper, it is necessary to know the process of decreasing the Pb content in the compost material. This study was conducted with the aim of comparing the Pb content after application of cow rumen fluid on a mixture of used paper containing ink and organic waste for 60 days with used paper with ink for 7 days. The objects in this study consisted of two groups, the first group was used paper containing ink mixed with organic waste in a ratio of 1:1, then cow rumen fluid was added and incubated for 60 days, while the second group was inked waste paper added with cow rumen fluid and incubated for 7 days. Pb test incubation using AAS (Atomic Adsorption Spectrophotometer) method. The data were statistically tested by Independent T Test on SPSS 23 Software. The conclusions obtained from this study were the incubation time of inked paper waste with the addition of rumen fluid showed that the difference in Pb levels was not significant. The Pb content in both experimental groups was in accordance with the provisions of SNI 19-7030-2004.

Investigation of The Uses of Some Bioadsorbans in Cr(VI) Removal from Water Solution

Heavy metals are one of the biggest threats to aquatic ecosystems from an environmental perspective. Aquatic ecosystems containing heavy metals because of reaching these industries after being used in various industries cause environmental pollution. In this study, the use of peach kernel (PK) as a bioadsorbent and its usability in the adsorption of Cr (VI) from an aqueous solution was investigated. Thus, it was desired to increase the economic value of these materials, which have low economic value, by investigating the possibilities of using them as bioadsorbent. On the other hand, it is aimed to contribute to the protection of both the aquatic environment and human health, and therefore to the prevention of environmental pollution, by removing heavy metals, which are polluting threats in aquatic ecosystems, with these materials. In the study, synthetically prepared wastewater containing Cr (VI) was used. These materials used as adsorbent were ground after drying in an oven at 105 °C for 24 hours and materials with 35 mesh sieve size were used in the experiments. Atomic Adsorption Spectrophotometer (AAS), Fourier Transform Infrared Spectroscopy (FT-IR), Brunauer-Emmett-Teller Isotherm Model (BET) and Scanning Electron Microscope (SEM) were used to determine the Cr (VI) concentration and characterization of the adsorbent. The low rate of removal efficiency obtained in the preliminary experiments conducted as raw led to the application of activation processes to the peach kernel. From the adsorption processes performed after the activation processes, the PK yield was 93%. It was concluded that the FT-IR results in the adsorbent can be evaluated as chemical adsorption. BET results showed that the surface area of the material decreased after the adsorption process, while SEM results were evaluated that the adsorbent surface was heterogeneous. In the study, maximum efficiency was reached under optimum conditions at pH 2, 0.5 g adsorbent amount, and 5 hours retention time. It has been observed that a removal capacity of 0.738 mg.g-1 per unit adsorbent was obtained with 0.5 g PK under optimum conditions. It was found to be suitable for the Langmuir isotherm model, which is one of the adsorption isotherm models. In the kinetic evaluation of the reaction, it was suitable for pseudo-second-order rate kinetics. All results revealed the usability of PK in Cr (VI) removal, especially because of the activation process.

Application of pollution assessment models in soil contaminated by heavy metals in two steel rods markets, Port Harcourt, Rivers State, Nigeria

Soil samples were collected at a depth of 0-30cm within two steel markets and a control site in Port Harcourt, Rivers State Nigeria to assess the level of heavy metals (Fe, Pb, Cu, Cd, Cr, Ni and As) in the environment. Atomic Adsorption Spectrophotometer was used to analyze the samples for heavy metals. The concentrations of all the heavy metals in the steel rods markets exceeded that of the control. The results indicated that heavy metals concentrations in the sites were in the order; Mile III > Kala > RSU. The average levels of contamination of heavy metals recorded followed the order Fe > Cr > Cu > Pb > Ni > As > Cd in Mile III, Fe > Pb > Cu > Cr > Ni > As > Cd in Kala and Fe > Cu > Pb > Cr > Ni > As > Cd in RSU (control). Mean concentrations obtained for heavy metals within the months of investigation were; 1420.931±9.155, 7.753±0.184, 8.730±0.050, 2.843±0.124, 9.428±0.122, 7.433±0.047 and 3.732±0.047 mg/Kg for Fe, Pb, Cu, Cd, Cr, Ni and As respectively at the mile III station, while the mean concentrations of heavy metals observed at the Kala station were; 1161.173±1.823, 9.425±0.054, 7.596±0.027, 1.425±0.020, 6.507±0.006, 5.455±0.033 and 1.901±0.010 mg/Kg for Fe, Pb, Cu, Cd, Cr, Ni and As respectively. The mean values of heavy metals concentrations observed at the RSU station within the period were; 892.064±1.025,5.603±0.007, 5.841±0.051, 0.173±0.005, 3.389±0.009, 2.309±0.010 and 0.706±0.006 mg/Kg for Fe, Pb, Cu, Cd, Cr, Ni and As respectively. Pollution assessment models used for assessing the anthropogenic input on the quality of the soil in the area using the control site as the basis of judgment were: contamination factor (CF), pollution load index (PLI), contamination degree (CD), modified contamination degree (mCD), potential ecological risk coefficient (Eir), potential ecological risk index (RI), Geo-accumulation index (Igeo) and anthropogenicity. These indices revealed that the steel markets were contaminated and polluted and poses ecological risks by heavy metals, even though the values obtained were still below the WHO acceptable limits. The steel rods markets need to be adequately monitored and regulated to avoid further soil contamination by heavy metals to a degree that will be dangerous to human health.

Hazard Analysis of Trace Metals in Muscle of Sarotherodon Melanotheron and Chrysichthys Nigrodigitatus from Okulu River, Rivers State, Nigeria

Introduction: An instance of fish deaths in marine waters surrounding some communities in Bonny and Andoni Local Government Areas in Rivers State was reported in March-April 2020. This study investigated trace metals hazard in muscle of Tilapia (Sarotherodon melanotheron) and Silver Catfish (Chrysichthys nigrodigitatus) from Okulu River, Rivers State, Nigeria. Materials and Methods: Tissues of 24 samples of Sarotherodon melanotheron and Chrysichthys nigrodigitatus obtained from the river were analyzed using atomic adsorption spectrophotometer, and the health risk was estimated based on estimated daily intake (EDI), target hazard quotient (THQ), and total target hazard quotient (TTHQ). Results: The concentration (mg/kg) of iron, zinc, manganese, copper, cadmium, lead, and chromium in both species ranged 4.00 – 197.30, 9.20 – 35.30, 0.20 – 5.00, 0.00 – 73.10, 0.00 – 1.30, 0.00 – 54.70, and 0.00 – 0.50, respectively. The EDI of trace metals resulting from the consumption of both fish species was higher than the permissible tolerance intake (PTI) mg/day/60kg body weight. The THQ and TTHQ were < 1, indicating that the consumption of this food fish portends no known health concern. However, the carcinogenic risks exceeded the threshold level of 10-6 - 10-4, thus, reflecting carcinogenic tendency. Based on the results obtained, it must be ensured that the effluents discharged into open water bodies meet the recommended limits. Conclusion: There is a need to create awareness among consumers of food fish in the study area. There should be periodic monitoring of trace metals in surface waters and its food fish population to forestall potential health impact on humans.

بررسی همدمای جذب روی و مس بر سطح اسید هومیک استخراج شده از خاک

Introduction: Copper and zinc are two of the most important microelements affecting plant growth which can be influenced by many factors. The adsorption processes play a determinative role in solubility of copper and zinc elements in the soil solution and, therefore, their availability to plants. Organic matter is one of the most important factor that have an significant role on the absorption and desorption of elements in the soil. These materials are divided into humic and non-humic groups. Humic substances are divided into three groups of fulvic acid, humic acid and humic, based on their resistance and solubility in acid and base. Humic acid with a medium molecular weight and color is soluble into base and insoluble into acid, and has a medium resistance against the microbial attack. It forms the most important organic part of the soil and is capable to adsorb metals. The purposes of this study were to extract soil humic acid, study the adsorption of metals on the surface of humic acid and to determine the metals adsorption coefficients using adsorption isotherm models. Materials and Methods: Sampling was done from forest areas of northern Iran. Some physical and chemical properties of the studied soil were determined. Then, the humic acid of the soils was extracted by 0.1 M NaOH and 6 M HCl, and purified by 0.1M HCl+0.3M HF. Functional group, E4/E6 ratio (Optical density or absorption of dilute solutions at wavelengths of 465 and 665 nm), and humification index of the extracted humic acid were measured. Some other properties of the extracted humic acid have also been analyzed. To study the adsorption isotherms of Zn and Cu in the presence of humic acid, solutions with concentrations of 10, 20, 40, 60 and 80 mg/L of ZnCl2 (zinc adsorption testing) and CuSO4 (copper adsorption testing) were prepared, respectively in a 0.01M Ca(NO3)2 background solution, and added to 250 g of humic acid. The samples were shaken for 12 hours (based on the time of equilibrium) at pH=5 and 25 °C in incubator shaker, then the samples were centrifuged and the supernatant was passed through filter paper and measured using atomic adsorption spectrophotometer device. The difference between initial concentration and final concentration identified the amount of adsorbed element. Results and Discussion: The results of the acidic functional groups measurement in the humic acid samples revealed that the most of total acidity (60%) was due to the presence of phenolic groups while the carboxylic groups were responsible for the remaining (40%). Phenolic groups were abundant in the primary stages of the decomposition of humic materials. Since the soil used for extracting humic acid was covered with broad leaf trees and the continuous entry of organic matter into it (the fall of leaves) lasted for many years and due to the low temperature of the soil in part of the year, it can be said that a significant part of the soil organic matter is in the primary or middle stages of humification and the phenolic OH groups/carboxylic groups ratio in the humic acid extracted from them was high. The equilibrium time for adsorption of both metals occured at 12 h to achieve maximum adsorption level in the presence of humic acid. The obtained experimental data were fitted to three models of Langmuir, Freundlich, and Tampkin. The accuracy of mentioned models to fit data were estimated based on the detection coefficient (R2) and the roots of mean square error (RMSE). The results showed that the Freundlich model with higher detection coefficient and lower roots of mean squared error describes the adsorption of copper and zinc elements, well. To better compare the adsorption of the elements by humic acid, Langmuir's b parameter (Expresses maximum adsorption) can be used. The maximum adsorption of copper (23.04 mg/g) by humic acid was higher than zinc adsorption (13.8 mg/g). This trend is consistent with the Irving–Williams series of divalent elements: Mn < Fe < Zn < Co < Ni < Cu. It is generally believed that humic acid is a good complexing agent for many metal ions and its binding to metal ions can improve the adsorption. Significance differences were tested by a parametric 𝑡-test or 𝐹 statistics in ANOVA (analysis of variance). There was a significant correlation between the maximum adsorption of metals (b) and the properties of humic acid at a probability level of 5%.

Adsorption of &amp;lt;i&amp;gt;Pb (II)&amp;lt;/i&amp;gt; and &amp;lt;i&amp;gt;Cd (II)&amp;lt;/i&amp;gt; Ions from Their Aqueous Solutions unto Carbonised Orange Peels

The presence of heavy metals in the environment and especially water is known to both cause severe harm to marine organisms, and also to terrestrial plants and animals including human beings. In an attempt to minimize environmental pollution caused by agricultural wastes and maximize agricultural by-products, the adsorption of Pb²⁺ and Cd²⁺ using carbonized orange peel as adsorbent was studied using batch adsorption method. The initial physico-chemical properties of the prepared adsorbent were 6.14, 10%, 12%, 2.0%, and 0.5mg/L for pH, attrition, ash content, moisture content and bulk density respectively. Atomic adsorption spectrophotometer was used to monitor the Pb²⁺ and Cd²⁺ concentrations of the simulated test solutions. The optimum values obtained were 97.34% at concentration of 40mg/L for Pb²⁺ and 93.45% at concentration of 20mg/L for Cd²⁺, 99.46% at a pH of 7 for Pb²⁺ and 97.48% at a pH of 6 for Cd²⁺, 96.76% at a contact time of 80 mins for Pb²⁺ and 50.05% at a contact time of 100 mins for Cd²⁺ and 97.36% at an adsorbent dosage of 1.2g for Pb²⁺ and 91.55% at an adsorbent dosage of 1.2g for Cd²⁺. The results indicated that carbonized orange peel is a good adsorbent for the removal Pb²⁺ and Cd²⁺ from simulated waste water.

Arsenic in Gold Mine Tailing and Agricultural Soil in Buru Island of Maluku

Contamination of heavy metal including Arsenic (As) due to mining activities decreased ecosystem quality. The objective of this study was to determine the arsenic level of tailing and agricultural soil, and evaluate the spatial distribution of As in closed gold mine and nearby agricultural area in Buru Sub-district of Maluku. Tailing and soil samples were taken by purposive method based on mining and agricultural activities. Arsenic level in tailing and soil samples was determined by Atomic Adsorption Spectrophotometer after mixed acid extraction. The study showed that gold mine increased As level in the top soil and tailing but soil of nearby agricultural area was not contaminated by As. Increased concentration of As in tailings has been verified. pH level of the agricultural area was neutral hence lowered As availability for plant.

Removal of Selected Heavy Metal Ions from Industrial Wastewater Using Rice and Corn Husk Biochar

This study investigated the removal of heavy metal ions from industrial wastewater by using rice and corn husk biochar. The choice of the materials was influenced by their large surface area, abundance of functional groups as well as their availability in the local environment. Rice and corn husks were pyrolyzed at 500, 600, and 700 °C to make biochars that were used to treat low-quality industrial wastewater. Initial metal ion levels in wastewater and residual levels after the application of biochars were measured using an atomic adsorption spectrophotometer. Carbonization of rice husks at 600 °C produced the best removal efficiencies for Cr (65%), Fe (90%), and Pb (> 90%). The carbonization of corn husks at 600 °C produced the worst removal efficiencies for Cr (only 20%) and Pb (slightly > 35%). Regardless of the carbonization temperature, rice husk biochars performed better than corn husk biochars. Experimental data fitted well the Langmuir and Freundlich isotherm models (R2 values ranging between 0.82 and 0.99). The Langmuir separation factor, RL, had negative values, probably due to the low initial concentration of the adsorbates in the raw wastewater. All the biochars showed a relatively short contact time (20 to 30 min) to attain maximum adsorption efficiencies and are a promising feature for future industrial applications. The studied biochar materials from rice and corn husk have the potential to remove heavy metal ions from industrial wastewater; rice husk biochar showed higher removal capacity than corn husk biochars.