scholarly journals Removal of orthophosphates in water by modified carbonate material of biological origin

2017 ◽  
Author(s):  
Marco Tadeu Gomes Vianna ◽  
Marcia Marques

The excessive release of phosphorus (P) by discharge of domestic and industrial effluents is directly associated with the eutrophication of water bodies. Therefore, an efficient removal of P from effluents is required. The method most commonly used for P removal from wastewater is chemical precipitation. However, this technique is relatively expensive and demands a proper disposal for the sludge. Therefore, the development of new materials with low cost but high P removal efficiency has been investigated. The introduction of exotic species in aquatic environments is considered a serious environmental problem in different parts of the world. Considering that, many of these species have high concentrations of carbonates in their exoskeleton composition, which is potentially useful in water treatment, particularly for P removal the use of such material as adsorbent has been tested. The present study aimed to investigate the capacity of the exoskeleton of exotic species in powder form to remove orthophosphates from water comparing the raw material (RCS), with physically modified (CSA) and chemically modified (CSC) material. To study the orthophosphates removal efficiency, a factorial design with central composite rotational design (CCRD) was applied. In order to optimize the P removal, the influence of the independent variables adsorbent/adsorbate ratio, pH and temperature was investigated with the kinetic control associate at each configuration obtained by CCRD. The P removal capacity of RCS varied from 125.0 mgP kg-1 to 1002.5 mgP kg-1; the removal capacity of CSA varied from 237.5 mgP kg-1 to 1540.0 mgP kg-1. The removal capacity of CSC varied from 5212.5 mgP kg-1 to 12672.5 mgP kg-1. Based on the preliminary results, the exoskeleton powder showed to be a potentially sustainable alternative as adsorbent material (mostly the chemically modified form CSC) useful in several applications, such as the treatment of urban and industrial wastewaters to prevent eutrophication of water bodies and population control of exotic species due to the commercial exploitation. 

2019 ◽  
Vol 32 (1) ◽  
pp. 73-78
Author(s):  
P. Janaki ◽  
R. Sudha ◽  
T.S. Sribharathi ◽  
P. Anitha ◽  
K. Poornima ◽  
...  

The adsorption performance of sulphuric acid treated low cost adsorbent synthesized by using Citrus limettioides peel as an effective raw material for the removal of cadmium(II) from water. The batch adsorption method was carried out to optimize some parameters like contact time, pH and adsorbent dose. The nonlinear isotherm equations were used to calculate the different isotherm constant of five isotherm models namely Freundlich, Langmuir, Dubinin-Radushkevich, Redlich-Peterson and Sips. The Langmuir monolayer adsorption capacity of chemically modified Citrus limettioides peel was found to be 287.60 mg g-1. The negative values of ΔGº and ΔHº showed that the adsorption process is spontaneous and exothermic.


Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 781 ◽  
Author(s):  
Wang ◽  
Zhang ◽  
Lv

The removal efficiency and mechanism of Cr(VI) removal from aqueous solution on semi-decomposed maize straw biochars pyrolyzed at 300 to 600 °C were investigated. The removal of Cr(VI) by the biochars decreased with pyrolysis temperature increasing from 300 to 600 °C, and the maximum removal capacity of Cr(VI) for maize straw biochar pyrolyzed at 300 °C was 91 mg/g at pH 2.0. The percentage removal of Cr(VI) rapidly decreased with pH increasing from 2.0 to 8.0, with the maximum (>99.9%) at pH 2.0. The variation of Cr(VI) and Cr(III) concentrations in the solution after reaction showed that Cr(VI) concentration decreased while Cr(III) increased and the equilibrium was reached after 48 h, while the redox potential after reaction decreased due to Cr(VI) reduction. X-ray photoelectron spectroscopy (XPS) semi-quantitative analysis showed that Cr(III) accounted for 75.7% of the total Cr bound to maize straw biochar, which indicated reductive adsorption was responsible for Cr(VI) removal by the biochars. Cr(VI) was firstly adsorbed onto the positively charged biochar surface and reduced to Cr(III) by electrons provided by oxygen-containing functional groups (e.g., C=O), and subsequently part of the converted Cr(III) remained on the biochar surface and the rest released into solution. Fourier transform infrared (FTIR) data indicated the participation of C=O, Si–O, –CH2 and –CH3 groups in Cr(VI) removal by the biochars. This study showed that maize straw biochar pyrolyzed at 300 °C for 2 h was one low-cost and efficient adsorbent for Cr(VI) removal from aqueous solution.


2017 ◽  
Author(s):  
Ala Kirjanova ◽  
Mindaugas Rimeika ◽  
Kristina Zopelytė

Column study was performed in order to compare phosphate phosphorus (PO4-P) removal capacity of iron filings and Filtralite P. The experiment with two vertical downflow columns (0.05 in diameter and with 0.9 m medium height) feeding synthetic wastewater was carried out over a period of 66 days at wastewater temperature of 17.2–21.8 ºC. The study also aimed to determine the effect of submergence of the medium on Filtralite P PO4-P removal potential. During the experiment the submerged Filtralite P sorbed almost double amount of PO4-P (1581 mg PO4-P/kg filter material or 662 mg PO4-P/m3 filter material) compared to the unsubmerged (881 mg PO4-P/kg filter material or 369 mg PO4-P/m3 filter material). In both cases PO4-P removal efficiency exceeded 90 % when pH in the effluent was higher than 9.5. Through the experimental period the iron filings removed 2249 mg PO4-P/kg filter material. When evaluating the amount of removed PO4-P per volume of filter material, the iron filings removed 2164 mg PO4-P/m3 filter material, i. e. 3.3 times more than the submerged Filtralite P did. In the case of iron filings the largest PO4-P amount was removed in the top layer (0–30 cm) of the filter material. The amount of removed PO4-P decreased and PO4-P removal efficiency increased with depth of the medium: in the top layer (0–30 cm) PO4-P removal efficiency was 27 %, whereas in the bottom layer (60–90 cm) it reached 44 %. The same tendency of PO4-P removal efficiency was observed in the column with the submerged Filtralite P; however, the PO4-P removal efficiency in all layers of this filter material was lower in comparison with the iron filings.


Author(s):  
Milena Emy Matsubara ◽  
Lúcia Helena Gomes Coelho

“Pozzolan” is a slag from the burning of coal in power plants which has the potential to assist as a low-cost adsorbent for wastewater treatment. The excess of Phosphorus (P) in the environment can promote chemical pollution and harm ecosystems, especially water. It is therefore necessary to implement inexpensive techniques and processes for the efficient treatment of water and wastewater. In this context, this study evaluated the use of the pozzolanic fly ash material for P removal from wastewater for the development of low-cost treatment technologies for environmental restoration and remediation of water resources. The treatment systems were developed in batch configuration. The removal tests from a synthetic sample with a known concentration of P reached a maximum of 30% removal in concentration, even varying the pH and performing different treatments of the pozzolanic material. This low removal efficiency of Phosphorus led to a comparative test between different lots of pozzolan in order to verify if the results obtained were characteristic of the material itself or of the lot obtained. Also the P adsorption isotherms were constructed with the two lots achieving adsorption capacities from 0.87 mg g-1 to 74 mg g-1. This difference indicates that the low P removal efficiency in the preliminary tests is due to the characteristics of the substrate of the first lot. Tests on a real effluent using the pozzolan from the second sample lot indicated a 99% efficiency of P removal, with an initial concentration of Phosphorus in the effluent of 5.5 mg L-1.


2017 ◽  
Author(s):  
Marco Tadeu Gomes Vianna ◽  
Marcia Marques

The objective of this study was to evaluate the adsorption capacity calcareous skeleton of animal species (CSAS) in powder form compared to the commercial activated carbon (CAC) powder, as adsorbent for orthophosphates (P) removal from water. The experimental design selected was a factorial design with central composite rotational design (CCRD). In order to optimize the sorption process, a number of independent variables and levels were selected including: adsorption time; adsorbent/adsorbate ratio; pH and temperature. The orthophosphate (P) quantification was performed using the 4500-P E method. The P removal capacity with CAC powder varied from 0.15 to 4.86 mg/L. The maximum removal occurred at 1088 min, initial pH of 7.5, adsorbent/adsorbate ratio of 130, and temperature of 27 ºC. With the CSAS, the phosphorus removal varied from 0.70 to 6.11 mg/L. The maximum removal occurred at 735 min, with initial pH of 9.0, adsorbent/adsorbate ratio of 40 and temperature of 32 ºC. The conclusion is that the CSAS powder can become an interesting alternative as adsorbent material, both from economic and technical viewpoints in several applications, such as treatment of urban and industrial wastewaters and phosphorus removal/ retention to prevent eutrophication of recipient water bodies. Additionally, the final product (phosphorus-adsorbed CSAS powder) can be used as fertilizer and as soil pH adjustment.


Author(s):  
O.Kameswara Rao ◽  
P. Venkateswarlu

The release of heavy metals into the environment is a worldwide major concern. Different studies have demonstrated that natural agents have a high removal capacity for divalent heavy metal ions. Wood ash is a natural adsorbent and, in comparison with others, has a very low price. In this study, the removal of heavy metals (Pb and Co) from Nippo Battery Industry (TADA, A.P.) effluent was investigated in batch condition. Pb and Co measurement in samples were done with atomic absorption equipment and test methods were adapted from standard methods for the examination of water and wastewater. The effect of pH and the amount of adsorbent was determined and different adsorption isotherms were also obtained. This study shows that the adsorption process follows the adsorption Langmuir isotherm. The amount of wood ash has a great role in the adsorption rate and adsorption rate increased as wood ash increased. In the study, the reactions reached equilibrium in 3 h contact time. The maximum Pb removal efficiency was 96.0% at pH 2 with a contact time of 3 h and 100 g/L wood ash and the maximum Co removal efficiency was 98.9 % at pH 2 with a contact time of 3 h and 100 g/L wood ash. According to the results, wood ash is recommended as a low cost and available adsorbent to remove Pb and Co from municipal and industrial wastewaters.


2020 ◽  
Vol 5 (3) ◽  
pp. 179-184
Author(s):  
Marianna Havryshko ◽  
◽  
Olena Popovych ◽  
Halyna Yaremko ◽  
◽  
...  

At the present stage of development, the entire world industry has faced the problem of rational use of renewable natural resources, in particular the most efficient ways of wastewater treatment and the use of accumulated waste in the production process as a secondary raw material. In particular, the alcohol industry, as one of the components of food, medical, chemical and various industries,leads to the formation of huge amounts of waste, including wastewater. The food industry, like any other industry, has a negative impact on the environment. Water bodies are the most affected by the food industry. Almost the first place in terms of water consumption per unit of production is the production of alcohol. Consumption of large amounts of water leads to the formation of wastewater, which is highly polluted and adversely affects the environment. Due to the high chemical and biological consumption of oxygen, specific color and odor, suspended solids, low pH value, the purification of such waste in the filtration fields and discharge into water bodies is not possible. The purpose of our work is: 1) conducting the analysis of the alcohol industry potential in Ukraine in recent years, and methods of waste disposal as a potential source for the development of bioenergy. 2) environmental aspects of the alcohol industry modernization at present stage of development and implementation of modern wastewater treatment technologies.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Xiao Li Ma ◽  
Guang Tao Fei ◽  
Shao Hui Xu

Abstract In this study, polyaniline (PANI) is prepared by means of chemical oxidization polymerization and directly loaded on the modified fiber ball (m-FB) to obtain macroscale polyaniline/modified fiber ball (PANI/m-FB) composite, and then its removal ability of Cr(VI) is investigated. The effects of different parameters such as contact time, pH value and initial concentration on Cr(VI) removal efficiency are discussed. The experimental results illustrate that the favorable pH value is 5.0 and the maximum removal capacity is measured to be 293.13 mg g−1. Besides, PANI/m-FB composites can be regenerated and reused after being treated with strong acid. The kinetic study indicates that the adsorption procedure is mainly controlled by chemical adsorption. More importantly, the macroscale of composites can avoid secondary pollution efficiently. Benefiting from the low cost, easy preparation in large scale, environmentally friendly, excellent recycling performance as well as high removal ability, PANI/m-FB composites exhibit a potential possibility to remove Cr(VI) from industrial waste water. Graphic Abstract The polyaniline (PANI) was coated on modified fiber ball (m-FB) to remove Cr(VI) in waste water, and this kind of PANI/m-FB composites can avoid secondary pollution efficiently due to its macrostructure. Furthermore, the removal capacity can reach to 291.13 mg/g and can be multiple reused.


Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 384
Author(s):  
Ahmed Labena ◽  
Ahmed E. Abdelhamid ◽  
Abeer S. Amin ◽  
Shimaa Husien ◽  
Liqaa Hamid ◽  
...  

Biosorption is a bioremediation approach for the removal of harmful dyes from industrial effluents using biological materials. This study investigated Methylene blue (M. blue) and Congo red (C. red) biosorption from model aqueous solutions by two marine macro-algae, Ulva fasciata and Sargassum dentifolium, incorporated within acrylic fiber waste to form composite membranes, Acrylic fiber-U. fasciata (AF-U) and Acrylic fiber-S. dentifolium (AF-S), respectively. The adsorption process was designed to more easily achieve the 3R process, i.e., removal, recovery, and reuse. The process of optimization was implemented through one factor at a time (OFAT) experiments, followed by a factorial design experiment to achieve the highest dye removal efficiency. Furthermore, isotherm and kinetics studies were undertaken to determine the reaction nature. FT-IR and SEM analyses were performed to investigate the properties of the membrane. The AF-U membrane showed a significant dye removal efficiency, of 88.9% for 100 ppm M. blue conc. and 79.6% for 50 ppm C. red conc. after 240 min sorption time. AF-S recorded a sorption capacity of 82.1% for 100 ppm M. blue conc. after 30 min sorption time and 85% for 100 ppm C. red conc. after 240 min contact time. The membranes were successfully applied in the 3Rs process, in which it was found that the membranes could be used for five cycles of the removal process with stable efficiency.


Author(s):  
T. G. Ambaye ◽  
M. Vaccari ◽  
E. D. van Hullebusch ◽  
A. Amrane ◽  
S. Rtimi

AbstractCurrently, due to the rapid growth of urbanization and industrialization in developing countries, a large volume of wastewater is produced from industries that contain chemicals generating high environmental risks affecting human health and the economy if not treated properly. Consequently, the development of a sustainable low-cost wastewater treatment approach has attracted more attention of policymakers and scientists. The present review highlights the recent applications of biochar in removing organic and inorganic pollutants present in industrial effluents. The recent modes of preparation, physicochemical properties and adsorption mechanisms of biochar in removing organic and inorganic industrial pollutants are also reviewed comprehensively. Biochar showed high adsorption of industrial dyes up to 80%. It also discusses the recent application and mechanism of biochar-supported photocatalytic materials for the degradation of organic contaminants in wastewater. We reviewed also the possible optimizations (such as the pyrolysis temperature, solution pH) allowing the increase of the adsorption capabilities of biochar leading to organic contaminants removal. Besides, increasing the pyrolysis temperature of the biochar was seen to lead to an increase in its surface area, while it decreases their amount of oxygen-containing functional groups, consequently leading to a decrease in the adsorption of metal (loid) ions present in the medium. Finally, the review suggests that more research should be carried out to optimize the main parameters involved in biochar production and its regeneration methods. Future efforts should be also carried out towards process engineering to improve its adsorption capacity to increase the economic benefits of its implementation.


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