Removal of Pb2+ Ions by ZSM-5/AC Composite in a Fixed-Bed Bench Scale System

This investigation suggests the implementation of ZSM-5 activated carbon composite as a prolific adsorbent for the continuous elimination of Pb2+ ions from water. Continuous adsorption experiments were performed by varying three parameters such as process flow rate (2-6 mL min-1), bed height (2-6 cm), and initial concentration (250–750 mg L-1). The highest loading capacity of the fixed-bed 213.3 mg L-1 was achieved with optimal values of 2 mL min-1 of flow rate, bed height of 6 cm, and initial concentration of 750 mg L-1, respectively. The breakthrough curves and saturation points were found to appear quickly for increasing flow rates and initial concentration and vice versa for bed depth. The lower flow rates with higher bed depths have exhibited optimal performances of the fixed-bed column. The mechanism of adsorption of Pb2+ ions was found to be ion exchange with Na+ ions from ZMS-5 and pore adsorption onto activated carbon. The breakthrough curves were verified with three well-known mathematical models such as the Adams-Bohart, Thomas, and Yoon-Nelson models. The later models showed the best fit to the column data over the Adams-Bohart model that can be utilized to understand the binding of Pb2+ ions onto the composite. Regeneration of ZSM-5/activated carbon was achieved successfully with 0.1 M HCl within 60 min of contact time. The outcomes conclude that ZSM-5 activated carbon composite is a prolific material for the continuous removal of water loaded with Pb2+ ions.

Biosorption of Malachite Green Dye from Wastewater with Henfeathers -Analysis of Various Mathematical Models Wrt Continuous Adsorption

In recent years, the remediation of hazardous organic dye-contaminated aquatic habitats has been a key research priority for environmental and chemical engineers. The goal of this research was to see how well malachite green adsorbs from waste water in a continuous column system having fixed bed. A biosorbent made from waste materials such as hen feathers has been shown to extract the water-soluble malachite green colour from waste water. The adsorption potential of malachite green dye ions in a continuous flow adsorption column is investigated in this work. The hen feathers' performance in the fixed bed column was assessed under a variety of operating circumstances, including bed height in the range 6-10cm; flow in the range 4-12ml/min, and starting concentration (10-30 mg/l). In comparison to other testing settings, the bed height (8cm), flowrate (12ml/min), and maximum input concentration (20mg/l) resulted in the highest malachite green absorption of 2.829mg/g. The column experimental data collected under various conditions was evaluated using three distinct models namely 1. Bohart-Adams model, 2 Yoon-Nelsons model, and 3 BDST model, all of which produced a decent estimation of the breakthrough curve. The findings from the Yoon-nelson and BDST models, on the other hand, were more favourable. The several characteristics of the hen feathers were studied using FTIR studies. The activated hen feather powder was a successful potential bio sorbent for the malachite green from aqueous phase.

Biosorption As A Perfect Technique for Purification of Wastewater Contaminated With Ammonia

Eichhornia Crassipes root powder (ECRP) has been used to remove ammonia from aqueous solutions. The biosorption factors such as biosorbent dosage, pH, initial ammonia concentration, and contact time have been considered in batch conditions. The optimal conditions, at pH (6), sorbent dose 5 g/l, time (30 min) ammonia concentration (10 mg/l). Langmuir is better suited than Freundlich isotherm. The kinetic models: Thomas, Yoon-Nelson, and Bohart-Adm were applied. These models showed that; the adsorption capacity decreased with flow rate increases as follows: (32.57, 31.82, 31.25, and 30.17 mg/gm) respectively at a flow rate (10, 15, 20, and 25 ml/min). The roots powder of Eichhornia Crassipes was used to treat specific drainage wastewater obtained from the Sabal drain at Menoufia, Egypt. The average efficiency of ammonia removal was 87% per batch adsorption method at pH value = 7.5, sorbent dose 5 g/L, uptake period (30 minutes), and primary load 7.1 mg/l; however, ammonia removal by column continuous adsorption method exceeded 94 %. In addition, (ECRP) has been shown to be efficient in removing arsenic, sulfate, nitrates, nitrite, silica, iron, manganese, copper, zinc, aluminum, and lead from actual sewage wastewater, in addition to removing more than 75 % COD.

Synthesis of Copper Nanoparticles from Cu2+-Spiked Wastewater via Adsorptive Separation and Subsequent Chemical Reduction

Copper in ionic form (Cu2+) should be removed from wastewater because of its harmful effects on human health. Meanwhile, Cu-metal nanoparticles (Cu0 NPs) are widely used in various applications such as catalysts, optical materials, sensors, and antibacterial agents. Here, we demonstrated the recovery of Cu2+ from wastewater and its subsequent transformation into Cu0 NPs, a value-added product, via continuous adsorption followed by chemical reduction by hydrazine. To separate and enrich Cu2+ from wastewater, a biosorbent that exhibits excellent selectivity and adsorption capacity toward Cu2+, i.e., polyethyleneimine-grafted cellulose nanofibril aerogel (PEI@CNF), was packed into a column and used to treat 20 mg/L Cu2+ wastewater at a flow rate of 5 mL/min. The Cu2+ adsorption reached equilibrium at 72 h, and the Cu2+-saturated column was eluted using 0.1 M of HCl. After five consecutive elutions of Cu2+ from the adsorbent column, a Cu2+-enriched solution with a concentration of 3212 mg/L was obtained. The recovered Cu2+ concentrate was chemically reduced to obtain Cu0 NPs by reaction with hydrazine as a reductant in the presence of sodium dodecyl sulfate (SDS) as a stabilizer. The solution pH and hydrazine/Cu2+ ratio strongly affected the reduction efficiency of Cu2+ ions. When 0.1 M of SDS was used, spherical 50–100 nm Cu0 NPs were obtained. The results demonstrate that Cu2+-spiked wastewater can be converted into Cu0 NPs as a value-added product via adsorption followed by chemical reduction.

Removal of Dyes from Wastewater of Artisanal Dyeing Plants by Adsorption in a Fixed Bed Column of Deactivated Lichens

Aims: Pollution by wastewaters from various urban activities such as artisanal dyeing plants is a real problem for developing countries. The treatment of wastewater by the adsorption method is carried out by means of less expensive and available adsorbent media. Two techniques of the adsorption method are possible: adsorption in continuous mode (column adsorption) and adsorption in discontinuous mode (batch adsorption). The choice of the continuous adsorption technique is justified by its ability to process large volumes of solutions. In this study, dyes contained in wastewater from artisanal dyeing plants were removed by continuous adsorption in a fixed-bed column of deactivated lichen biomass (Parmotrema dilatatum). Study Design: Random design Place and Duration of Study: Laboratory of Thermodynamics and Environmental Physico-Chemistry (University Nangui Abrogoua, Ivory Coast) between May 2020 and October 2020. Methodology: Four (4) categories of wastewater were collected in artisanal cotton and leather dyeing plants through two municipalities of the city of Abidjan, economic capital of Ivory Coast. Two (2) wastewaters colored in blue from dyeing of cotton boubous and jeans and two (2) wastewaters colored in red from dyeing of leather jackets and bags. These wastewaters were treated through the fixed bed column of deactivated lichens. The column feed rate was set at 0, 07 L.min-1 and the adsorbent bed mass at 100 g. Results: The study showed that, regardless of the nature of the dyed object and regardless of the target dye, the amount of dye adsorbed was better with waters of higher initial concentration. Thus the best amount of adsorbed dye is 44.444 mg.g-1 and the best removal rate is 97.9%. These values are obtained with the red wastewater of bags (RWB) treatment which was the most concentrated wastewater. Conclusion: Good efficiency of deactivated lichen bed as adsorbent for the in situ removal of dyes from wastewater by continuous adsorption.