scholarly journals Effective Removal of Cr(VI) from Wastewater Using Biochar Derived from Walnut Shell

2021 ◽  
Vol 18 (18) ◽  
pp. 9670
Author(s):  
Tanzeela Kokab ◽  
Hafiza Sumbal Ashraf ◽  
Muhammad Bilal Shakoor ◽  
Asim Jilani ◽  
Sajid Rashid Ahmad ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Large Scale ◽  
Walnut Shell ◽  
Small Scale ◽  
Toxic Heavy Metal ◽  
Modern Age ◽  
Effective Removal ◽  
Scale Levels ◽  
High Concentrations

Heavy metals are the major concern of the modern age. Among the heavy metals, chromium (Cr(VI)) is regarded as a highly toxic heavy metal released largely from leather tanning operations. To remove such high concentrations of Cr(VI), an advanced method is required urgently. Thus, biosorption using biochar, which is an organic material produced from various sources such as walnut shell, can be applied successfully for Cr(VI) abatement. The major objectives of this experiment were the remediation of the Cr(VI) heavy metal using walnut shell biochar and checking of the effect of pH, biochar dosage, Cr level, and shaking time. Remediation of Cr(VI) using walnut shell biochar was proved to be effective and removed the maximum concentration of Cr(VI) up to 93% at pH 5.5, 2 h agitation time, and the biochar amount of 1.1 g L−1 from an aqueous solution. Equilibrium modeling demonstrated that the chemisorption process was involved in adsorption of Cr(VI). The surface of the biochar was porous and provided numerous sites for Cr(VI) attachment, which was also confirmed by the presence of Cr(VI) onto the biochar after adsorption. Hence, the use of walnut shell biochar was highly effective as a sorbent, which could conveniently be applied to small-scale as well as large-scale levels.

SYNTHESIS AND REMOVAL OF HEAVY METAL FROM WATER BODIES USING BIOSORBENT (HYDROGEL AGAR-AGAR) ADSORBENTS.

2021 ◽  
pp. 55-58
Author(s):  
Nilakantha Dash
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Aquatic Environment ◽  
Large Scale ◽  
Wide Spectrum ◽  
High Surface ◽  
Internal Surface ◽  
Polluted Water ◽  
Aqueous Environment ◽  
High Concentrations

Heavy metals (Cadmium, Nickel, Lead and chromium) which are natural components of the Earth's crust are usually associated with toxicity. Exposure to heavy metal , even at trace level, is known to be a risk for human being . The presence of zinc, heavy metals, nickel and others metal in the aqueous environment has potentially damaging effect on human physiology and other biological system when the acceptable levels are exceeded. Heavy metals (Heavy metals),Nickel(NI) ,Lead(Pb), Chromium are the common heavy metal and is often released into aquatic environment during mining activities and metallurgical processes. At high concentrations, heavy metal are highly toxic to most organisms and can be accumulated in organisms before entering human body through food chains. Many technologies have been developed to remediate heavy metals contamination, among which Biosorbents hydrogel Agar-agar is one of the most sustainable and promising. However, high pricing of Biosorbents today is plaguing its large –scale applications. The increased use of heavy metal in industry has resulted in increased availability of metallic substances in natural water sources. Many technologies like adsorption, precipitation , membrane ltration, and ion –exchange have been used to remove metal pollutants from water. However , adsorption has proven to be economical and efcient for removing heavy metal, organic pollutants and dyes form polluted waters. Several adsorbents such as Biosorbents and Silica can be used in the purication of water. Biosorbents has shown to be an efcient adsorbent for the removal of a wide variety of organic and inorganic contaminants present in the aquatic environment. Because of its high surface areas is widely used in the treatment of wastewaters. The effectiveness of Hydrogel Agar-agar in cleaning up polluted water is due to its well developed porosity structure as well as the presence of a wide spectrum of surface functional groups. This makes it capable of distributing pollutants on its large internal surface , making them accessible to reactants.

ASSESSMENT OF HEAVY METAL CONCENTRATION IN COCONUT WATER

1970 ◽  
pp. 07-10
Author(s):  
MdDidarul Islam, Ashiqur Rahaman, Aboni Afrose
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Heavy Metal Concentration ◽  
Coconut Water ◽  
Toxic Heavy Metals ◽  
High Concentration ◽  
Toxic Heavy Metal ◽  
Low Concentration ◽  
Wet Ashing ◽  
Aas Method

This study was based on determining concentration of essential and toxic heavy metal in coconut water available at a local Hazaribagh area in Dhaka, Bangladesh. All essential minerals, if present in the drinking water at high concentration or very low concentration, it has negative actions. In this study, fifteen samples and eight heavy metals were analyzed by Atomic Absorption Spectroscopy (AAS) method which was followed by wet ashing digestion method. The concentration obtained in mg/l were in the range of 0.3 to 1.5, 7.77 to 21.2, 0 to 0.71, 0 to 0.9, 0 to 0.2, 0.9 to 17.3, 0.1 to 0.9, 0 to 0.9 and 0 to 0.7 for Fe, Ni, Cu, Cd, Cr, Zn, Pb and Se respectively. From this data it was concluded that any toxic heavy metals like Cd, Cr, Pb and Ni exceed their toxicity level and some essential nutrients were in low concentration in those samples. 

scholarly journals A Short Review on Recent Advances of Hydrogel-Based Adsorbents for Heavy Metal Ions

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 864
Author(s):  
Suguna Perumal ◽  
Raji Atchudan ◽  
Thomas Nesakumar Jebakumar Immanuel Edison ◽  
Rajendran Suresh Babu ◽  
Petchimuthu Karpagavinayagam ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Large Scale ◽  
Water Bodies ◽  
Dimensional Structure ◽  
High Porosity ◽  
Adsorption Method ◽  
Toxic Heavy Metal ◽  
Practical Applications

The growth of industry fulfills our necessity and promotes economic development. However, pollutants from such industries pollute water bodies which pose a high risk for living organisms. Thus, researchers have been urged to develop an efficient method to remove toxic heavy metal ions from water bodies. The adsorption method shows promising results for the removal of heavy metal ions and is easy to operate on a large scale, thus can be applied to practical applications. Numerous adsorbents were developed and reported, among them hydrogels, which attract great attention because of the reusability, ease of preparation, and handling. Hydrogels are generally prepared by the cross-linking of polymers that result in a three-dimensional structure, showing high porosity and high functionality. They are hydrophilic in nature because of the functional groups, and are non-toxic. Thus, this review provides various methods of hydrogel adsorbents preparation and summarizes recent progress in the use of hydrogel adsorbents for the removal of heavy metal ions. Further, the mechanism involved in the removal of heavy metal ions is briefly discussed. The most recent studies about the adsorption method for the treatment of heavy metal ions contaminated water are presented.

Effects of shape and scale in mechanics of elastic interaction of regular wavy surfaces

2016 ◽  
Vol 231 (3) ◽  
pp. 332-340 ◽  
Author(s):  
Ivan Y Tsukanov
Keyword(s):  
Pressure Distribution ◽  
Entire Range ◽  
Large Scale ◽  
Elastic Interaction ◽  
Sine Wave ◽  
Wavy Surface ◽  
Small Scale ◽  
Scale Levels ◽  
Wavy Surfaces ◽  
Physical Effects

The physical effects associated with the shape and the scale of regular wavy surface asperities are investigated analytically. A special periodic analytical function, which is a generalization of a sine wave and allows to describe waviness of arbitrary smooth shape is suggested. The formulation and solution of the plane problem of elastic contact of a wavy surface with a half-plane is considered. Asperities of two-scale levels are taken into account—regular waviness with arbitrary shape (small-scale asperities) and regular sine-shaped roughness (large-scale asperities). The obtained pressure distribution for an arbitrary shaped one-scale wave is a generalization of the Westergaard’s solution for a sine wave. The results show that the shape of asperities has significant influence on pressure distribution over the entire range of contact lengths. It is also shown that the elastic coupling of adjacent asperities and asperities of different scales increases the nonlinearity of the contact interaction. But for the small loads the problem can be approximately reduced to linear, and the contact area fraction can be obtained directly from the geometry of contacting surfaces.

scholarly journals Estimation of the Concentration of Some Heavy Metals in Groundwater in Rutba City

2021 ◽  
Vol 904 (1) ◽  
pp. 012009
Author(s):  
A W Abd Byty ◽  
M A Gharbi ◽  
A H Assaf
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Large Scale ◽  
Toxic Metal ◽  
Scale Production ◽  
Future Health ◽  
Distribution Maps ◽  
Guideline Values

Abstract Toxic metal pollutants in groundwater should be identified to prevent future health risks. In this paper, the presence of heavy metals in groundwater in the western region of Iraq was investigated. The heavy metals concentrations, including Ni2+, Co2+, Zn2+, Pb2+, Cr3+, Cd2+, As3+ and Hg2+ were explored in twenty selected aquifers near Rutba City and the results were presented as spatial distribution maps. Findings indicate that contamination with the investigated heavy metal ions possesses a serious threat to the study area’s groundwater quality when compared to WHO and IEPA guideline values. Thus, a new approach to remove or adsorb heavy metal ions can be developed for large-scale production and the safe use of these aquifers water. Results revealed that the highest concentrations in mg/L1 of 2.312 in w19, 1.098 in w2, 5.78 in w17, 0.292 in w9, 3.349 in w5, 0.32 in w13, 0.074 in w11 and 5.622 in w1 for Zn2+, Cr3+, As3+, Pb2+, Ni2+, Co2+, Cd2+ and Hg2+ were recorded, respectively.

scholarly journals Scope and future perspectives of phytoremediation

2021 ◽  
Vol 16 (AAEBSSD) ◽  
pp. 77-85
Author(s):  
Sridevi Tallapragada ◽  
Rajesh Lather ◽  
Vandana ◽  
Gurnam Singh
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Genetic Engineering ◽  
Plant Growth ◽  
Mycorrhizal Fungi ◽  
Large Scale ◽  
Negative Impact ◽  
Heavy Metal Accumulation ◽  
Plant Growth Promoting Bacteria ◽  
Runoff Water

Phytoremediation is the plant-based technology that has emerged as a novel cost effective and ecofriendly technology in which green plants are used for extraction, sequestration and/or detoxification of the pollutants. Plants possess the natural ability to degrade heavy metals and this property of plants to detoxify contaminants can be used by genetic engineering approach. Currently, the quality of soil and water has degraded considerably due heavy metal accumulation through discharge of industrial, agricultural and domestic waste. Heavy metal pollution is a global concern and a major health threat worldwide. They are toxic, and can damage living organisms even at low concentrations and tend to accumulate in the food chain. The most common heavy metal contaminants are: As, Cd, Cr, Cu, Hg, Pb and Zn. High levels of metals in soil can be phytotoxic, leading to poor plant growth and soil cover due to metal toxicity and can lead to metal mobilization in runoff water and thus have a negative impact on the whole ecosystem. Phytoremediation is a green strategy that uses hyperaccumulator plants and their rhizospheric micro-organisms to stabilize, transfer or degrade pollutants in soil, water and environment. Mechanisms used to remediate contaminated soil includes phytoextraction, phytostabilization, phytotransformation, phytostimulation, phytovolatilization and rhizofiltration. Traditional phytoremediation method presents some limitations regarding their applications at large scale, so the application of genetic engineering approaches such as transgenic transformation, nanoparticles addition and phytoremediation assisted with phytohormones, plant growth-promoting bacteria and Arbuscular mycorrhizal fungi (AMF) inoculation has been applied to ameliorate the efficacy of plants for heavy metals decontamination. In this review, some recent innovative technologies for improving phytoremediation and heavy metals toxicity and their depollution procedures are highlighted.

scholarly journals Heavy Metals in the Soils of Placer Small-Scale Gold Mining Sites in Myanmar

2020 ◽  
Vol 10 (27) ◽  
pp. 200911
Author(s):  
Aung Zaw Tun ◽  
Pokkate Wongsasuluk ◽  
Wattasit Siriwong
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Gold Mining ◽  
Soil Samples ◽  
Small Scale ◽  
Mining Activities ◽  
Mining Operations ◽  
Metal Concentrations ◽  
Mining Sites ◽  
Heavy Metal Concentrations

Background. Artisanal and small-scale mining activities are widely practiced globally. Concentrations of heavy metals associated with gold, such as copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb) can increase in the environment as a result of mining activities, leading to environmental pollution and pose toxicity risks to humans and animals. Objectives. The aim of the present study was to investigate soil concentrations of toxic heavy metals in placer small-scale gold mining operations in Myanmar. Methods. Soil samples were collected from three placer small-scale gold mining sites: Site A located in the Hmawbon public protected forest, Site B and Site C, situated in the Nant-Kyin reserved forest around Nar Nant Htun village. At each site, soil samples were collected from four gold mining stages (ore processing, sluicing, panning, and amalgamation). Atomic absorption spectroscopy was utilized to examine the concentrations of As, Cd, Pb, and Hg. Results. The highest heavy metal concentrations were generally found in the amalgamation stages across all the gold mining sites. Across the three mining sites, the maximum heavy metal concentrations in the amalgamation stage were 22.170 mg.kg−1 for As, 3.070 mg.kg−1 for Cd, 77.440 mg.kg−1 for Hg, and 210.000 mg.kg−1 for Pb. Conclusions. The present study examined the concentrations of As, Cd, Hg and Pb in the soil of several small-scale gold mining sites in Banmauk Township, Myanmar. The results demonstrated the presence of high concentrations of heavy metals in the soil of the gold mining sites. Miners in this area work without proper personal protective equipment, and frequent exposure to heavy metals in the soil may cause adverse health effects. The present study provides baseline data for future risk assessment studies of heavy metal contamination in gold mines. Competing Interests. The authors declare no competing financial interests

scholarly journals Effects of Ectomycorrhizal Fungi and Heavy Metals (Pb, Zn, and Cd) on Growth and Mineral Nutrition of Pinus halepensis Seedlings in North Africa

2020 ◽  
Vol 8 (12) ◽  
pp. 2033
Author(s):  
Chadlia Hachani ◽  
Mohammed S. Lamhamedi ◽  
Claudio Cameselle ◽  
Susana Gouveia ◽  
Abdenbi Zine El Abidine ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
North Africa ◽  
Mineral Nutrition ◽  
Contaminated Soils ◽  
Mycorrhizal Fungi ◽  
Pinus Halepensis ◽  
Translocation Factor ◽  
Contaminated Sites ◽  
High Concentrations

The pollution of soils by heavy metals resulting from mining activities is one of the major environmental problems in North Africa. Mycorrhizoremediation using mycorrhizal fungi and adapted plant species is emerging as one of the most innovative methods to remediate heavy metal pollution. This study aims to assess the growth and the nutritional status of ectomycorrhizal Pinus halepensis seedlings subjected to high concentrations of Pb, Zn, and Cd for possible integration in the restoration of heavy metals contaminated sites. Ectomycorrhizal and non-ectomycorrhizal P. halepensis seedlings were grown in uncontaminated (control) and contaminated soils for 12 months. Growth, mineral nutrition, and heavy metal content were assessed. Results showed that ectomycorrhizae significantly improved shoot and roots dry masses of P. halepensis seedlings, as well as nitrogen shoot content. The absorption of Pb, Zn, and Cd was much higher in the roots than in the shoots, and significantly more pronounced in ectomycorrhizal seedlings—especially for Zn and Cd. The presence of ectomycorrhizae significantly reduced the translocation factor of Zn and Cd and bioaccumulation factor of Pb and Cd, which enhanced the phytostabilizing potential of P. halepensis seedlings. These results support the use of ectomycorrhizal P. halepensis in the remediation of heavy metal contaminated sites.

Effective removal of Cr(vi) using β-cyclodextrin–chitosan modified biochars with adsorption/reduction bifuctional roles

RSC Advances ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 94-104 ◽  
Author(s):  
Xixian Huang ◽  
Yunguo Liu ◽  
Shaobo Liu ◽  
Xiaofei Tan ◽  
Yang Ding ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Aqueous Solutions ◽  
Low Cost ◽  
Walnut Shell ◽  
Beta Cyclodextrin ◽  
Effective Removal ◽  
Adsorption Reduction

In this work, beta-cyclodextrin–chitosan modified walnut shell biochars (β-CCWB) were synthesized as a low-cost adsorbent for the removal of heavy metal Cr(vi) from aqueous solutions.

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