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Showing 7 results for Sorbent
Application of Rice Husk Biochar to Desalinate Irrigation Water
R. Rostamian, M. Heidarpour, S.f. Mousavi, M. Afyuni,
Volume 19, Issue 71 (6-2015)
Abstract

In recent years, use of carbon-based adsorbents has increased in pollution reduction from aqueous solutions. Biochar is a carbon-rich porous material, with low costs, and environmentally friendly, which is prepared by pyrolysis of biomass. In this study, potential of rice husk biochar to desalinate irrigation water with EC of 5, 15 and 25 dS/m was investigated. The effect of pyrolysis temperatures of 400 (RHB4), 600 (RHB6) and 800 (RHB8) on selected physicochemical characteristics and their desalination power was considered. The results showed that pyrolysis temperature has a significant effect on biochar properties. RHB6 with 301.1 mg g-1 desalination capacity was more efficient than the other biochars. This adsorbent had maximum surface area (211 m2 g-1) and total pore volume (0.114 cm3 g-1). The results of this study could open new horizons to manage the agricultural wastes and simultaneously reduce the cost of irrigation water.


Effects of Some Organic Matter and an Artificial Moisture Absorbent on Soil Available Water, Delay of Permanent Wilting Point and the Growth of Lysimachia Nummularia cv. Aurea
A. Mohammadi Orkashvand1, S. Sedaghat Hoor2, H. Jamalpour,
Volume 20, Issue 75 (5-2016)
Abstract

In this study, the impact of some organic matters and a moisture super absorbent were investigated on available water and delay of permanent wilting point in a sample soil of Rasht landscape. In incubation stage, 12 Treatments including control (70% v/v soil with 30% of the composted manure) and various amounts of soil, municipal compost, composted manure, olives and rice wastes along with a super absorbent (A200) were used in a completely randomized design. In order to provide water-release curve and to determine the amount of moisture needed for Field Capacity (FC) and Permanent Wilting Point (PWP), filter paper method was used. Three treatments having more available moisture and further delay in permanent wilting point in incubation stage were being applied in greenhouse stage, along with the control treatment. In greenhouse stage, impact of treatments and irrigation period (36, 72 and 168 hours) were studied on plant growth of Lysimachia, in a factorial experiment based on randomized complete block design. Results showed that the greatest weight of shoot dry matter was obtained in 30% municipal waste compost treatment and rice wastes treatment in 36 hours irrigation period, but at 168 hours period, dry matter decreased and the greatest dry matter was obtained from superabsorbent treatment. 


The Effect of Zeolite and Bentonite on the Bioavailability of Zinc, Cadmium and Lead in a Contaminated Soil under Sunflower Cultivation
Msc S. Shahmoradi, Dr M. Afyuni, Dr M. Hajabbasi, Dr A. H. Khoshgoftarmanesh, Dr M. Shirvani,
Volume 21, Issue 2 (8-2017)
Abstract
During last century, waste water of gold mine has accumulated heavy metals such as lead, zinc and cadmium in Zarshuran region soil, and thus has increased epidemic disease in this region drastically. The purpose of this research was to reduce the mobility and bioavailability of zinc, lead and cadmium in rhizosphere of sunflower grown in soil around the mine by inorganic sorbents. A pot experiments was carried out with three levels of raw zeolites (1, 6, 12 wt%), three levels of raw bentonite (1, 6, 12 wt%) and control (without sorbent) in a completely randomized block design with three replications. After cultivation, soil and plant samples were taken and the concentration of lead, cadmium and zinc in their samples were measured. Different levels of bentonite reduced the absorbable concentration of lead and zinc; and also reduced their absorbable concentrations in plant tissue, but had no significant effect on reducing absorbable concentration of cadmium.  Transfer factor for all three metals in the roots was more than shoot and reducing the concentration of heavy metals in the plant had no impact on plant growth. According to the study, level of 12 wt% of the raw bentonite was the most suitable sorbent for the stabilization of lead and zinc; and level of 12 wt% for raw zeolite was the best sorbent for stabilization of cadmium.

The Effects of Soil Ameliorating Hydrogels on Root System Characteristics of Avena fatua in Two Different Soil Textures
M. Rezashateri, S. J. Khajeddin, S. H. Matinkhah, M. M. Majidi,
Volume 21, Issue 2 (8-2017)
Abstract

This research investigated the effects of super absorbentpolymers on root characteristics of Avena fatua under two soil textures and three irrigation regimes. The study was arranged according to a factorial experiment based on a completely randomized design with three replications. Hydrogel compositions included three types of super absorbents (Aquasorb, Boloorab A and Stockosorb) with two levels of 5 and 10 g/kg of soil, plus a control level. The studied traits were shoot height, shoot dry weight, root dry weight, ratio of root/shoot, root length, root perimeter and root volume of Avena fatua. ANOVA showed that the effect of soil texture was significant (p<0.01) for all studied traits. Mean comparison stated that 10g/kg of Aquasorb with 100% irrigation in sandy loam texture and 5g/kg of Stockosorb with 100% irrigation in loamy texture had the most significant and best results, compared with the control treatments. The results revealed that production of dense root network and root aggregation stimulated by super absorbent polymers, increased root contacts with moisture and led to significant increment in root traits like length, perimeter and volume by preparing water. In addition, selecting the type and concentration of super absorbent polymers depends on soil texture, considering the difference between the best results in two soil textures.
 


Removal of Lead from Aqueous Solutions by Polyacrylic Acid-Bentonite Composite: Batch and Column Studies
M. Khamseh Mahabadi, M. Shirvani, M. R. Mosaddeghi,
Volume 24, Issue 1 (5-2020)
Abstract
Shortage of water resources and deterioration of water quality have urged the need to develop new technologies for the removal of contaminants from water. Heavy metals produced by municipal and industrial activities are among the most toxic contaminants present in the natural and waste waters. Different methods have been developed for the elimination of heavy metals from water resources and industrial waste waters. Adsorption is an effective and economic method for the water purification purposes. Nowadays, clays and natural polymers have been widely used as the adsorbents for heavy metals, due to their eco-friendly nature, natural abundance, low cost and high specific surface area. If these adsorbents are used as a hybrid material, some of their physical and chemical restrictions would be alleviated. In this study, polyacrylic acid–bentonite hybrids and natural bentonite were compared in terms of Pb adsorption in the batch and fixed-bed column systems. Besides, the effect of pH on Pb retention was investigated in both systems. The results of the batch studies showed that Langmuir and Freundlich isotherm models were appropriate in ing quilibrium Pb sorption data. Pb sorption by the sorbents was increased with the rise in solution of pH from 4 to 6, showing the greatest Pb sorption capacity at pH values of 4 (83.29 mg g-1) and 6 (103.3 mg g-1). Different indices of filtration and adsorption, including average relative effluent concentration, relative adsorption index, relative transmitted index, and filtration coefficient, were calculated from the break-through curves, indicating that the polyacrylic acid-bentonite nanocomposite was superior in the Pb sorbtion, as compared to bentonite. Also, a higher pH value resulted in the greater Pb removal from the solutions.  

Optimization of the Mixing Scheme of the Porous Concrete to Reduce Urban Runoff
M. Javaheri Tehrani, S. F. Mousavi, J. Abedi Koupai, H. Karami,
Volume 24, Issue 2 (7-2020)
Abstract
In the last few decades, the use of porous concrete to cover the sidewalks and pavements as an interface to collect the urban runoff has been increased. This system is economically more efficient than other runoff-pollution reduction methods. To design a runoff control system and reduce its pollution, it is necessary to determine the hydraulic and dynamic properties of the porous concrete (with and without additives). In this research, the effects of cement type (2 and 5), water to cement ratio (0.35, 0.45 and 0.55), fine grains percent (0, 10 and 20%), the type of additive (pumice, industrial pumice, perlite and zeolite), and the added additive percent (5, 10, 15 and 20%) on the physical properties of the porous concrete (porosity, hydraulic conductivity and compressive strength), each with three replications,  were  investigated using robust design. Qualitek-4 software was also used to discuss the results. The results showed that to obtain the highest porosity in the mixing scheme of the porous concrete, no fine grains, cement type 2 and 15% industrial pumice should be used, and water to cement ratio should be 0.35. Also, the water to cement ratio of 0.55, 0% fine grains, type 2 cement and 15% industrial pumice resulted in the highest value of hydraulic conductivity in the porous concrete. Finally, the water to cement ratio of 0.55, 20% fine grains, type 2 cement and 5% zeolite led to the maximum compressive strength. In general, it was not possible to reach a logical conclusion in this research with the least costs without employing the robust design.

Use of Modified Nano Particles of Beech Leaves for Nitrate Removal from Aqueous Solutions in the Column System
T. Dehgan, M. A. Gholami Sefidkouhi, M. Khoshravesh, N. Samadani Langroudi,
Volume 25, Issue 1 (5-2021)
Abstract
In this research, the nitrate removal by beech leaves was investigated in batch and column systems. The batch experiment was performed to address the effect of pH, contact time, adsorbent dosage and initial nitrate ion concentration on the nitrate removal. The results showed that with an increase in pH, the removal efficiency and adsorption capacity were decreased and nitrate removal by millimeter and nano adsorbent beech leaves reached equilibrium 120 and 90 minutes after experiment, respectively. With an increase in the nitrate concentration, the removal efficiency was decreased from 59.2% to 39.7% and 82.1% to 69.9% for millimeter and the nanoparticles of Beech leaves, respectively. In fixed-bed column adsorption experiments, the flow rates of 5, 8 and 11 ml/min and the nitrate concentration of 15, 50 and 120 mg/L were studied. The results showed with an increase in the nitrate concentration from 15 to 120 mg/L, the saturation time was decreased from 240 to 150 and 360 to 270 minutes for millimeter and nanoparticles of Beech leaves, respectively. Thomas, Dose-response and Yoon-Nelson models were fitted to the results of the continuous experiments. The Thomas model fitted the experimental data with high accuracy. Compared to the adsorbents, nano-adsorbent had more adsorption capacity in the batch and column systems. 

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