Graphene has attracted multidisciplinary study because of its unique physicochemical properties. Herein, few-layered graphene oxide nanosheets were synthesized from graphite using the modified Hummers method, and were used as sorbents for the removal of Cd(II) and Co(II) ions from large volumes of aqueous solutions. The effects of pH, ionic strength, and humic acid on Cd(II) and Co(II) sorption were investigated. The results indicated that Cd(II) and Co(II) sorption on graphene oxide nanosheets was strongly dependent on pH and weakly dependent on ionic strength. The abundant oxygen-containing functional groups on the surfaces of graphene oxide nanosheets played an important role on Cd(II) and Co(II) sorption. The presence of humic acid reduced Cd(II) and Co(II) sorption on graphene oxide nanosheets at pH < 8. The maximum sorption capacities (Csmax) of Cd(II) and Co(II) on graphene oxide nanosheets at pH 6.0 ± 0.1 and T = 303 K were about 106.3 and 68.2 mg/g, respectively, higher than any currently reporte...

Few-Layered Graphene Oxide Nanosheets As Superior Sorbents for Heavy Metal Ion Pollution Management

Textile industries are responsible for one of the major environmental pollution problems in the world, because they release undesirable dye effluents. Textile wastewater contains dyes mixed with various contaminants at a variety of ranges. Therefore, environmental legislation commonly obligates textile factories to treat these effluents before discharge into the receiving watercourses. The treatment efficiency of any pilot-scale study can be examined by feeding the system either with real textile effluents or with artificial wastewater having characteristics, which match typical textile factory discharges. This paper presents a critical review of the currently available literature regarding typical and real characteristics of the textile effluents, and also constituents including chemicals used for preparing simulated textile wastewater containing dye, as well as the treatments applied for treating the prepared effluents. This review collects the scattered information relating to artificial textile wastewater constituents and organises it to help researchers who are required to prepare synthetic wastewater. These ingredients are also evaluated based on the typical characteristics of textile wastewater, and special constituents to simulate these characteristics are recommended. The processes carried out during textile manufacturing and the chemicals corresponding to each process are also discussed.

https://link.springer.com/content/pdf/10.1007/s13762-018-2130-z.pdf

Textile dye wastewater characteristics and constituents of synthetic effluents : a critical review

https://nasport.pmf.ni.ac.rs/publikacije/185/+Removal%20of%20Pb(II)%20ions%20from%20aqueous%20solutions%20by%20adsorption%20onto%20pine%20cone%20activated%20carbon.pdf

Removal of lead(II) ions from aqueous solutions by adsorption onto pine cone activated carbon

pH dependent Cu(II) and Pd(II) ions detection and removal from aqueous media by an efficient mesoporous adsorbent

Comparative study of heavy metal ions sorption onto activated carbon, carbon nanotubes, and carbon-encapsulated magnetic nanoparticles

Removal of lead copper chromium and cobalt ions onto granular activated carbon in batch and fixed-bed adsorbers

The single component and multi-component hydroxide pr cipitation and adsorption were studied for different heavy metals namely Iron (III), Chromium (III), Copper (II), Lead (II), Nickel (II), and Cad mium (II) from aqueous solutions. By using the jar tester Magnesia (MgO) was used as a precipitator at different doses and compared with other chemicals like lime ( CaO) and caustic soda (NaOH). The treatment involves the addition of eith r magnesia or lime-water suspensions (combined with cationic polyelectrolyte , CPE) in various doses, 1.0 – 5.0 g/l for the metal samples to study the effect o f varying doses on the treatment efficiency. The results show that the percent remov al f metal ions increases to about 99 % with increasing the MgO dose to some lim its. The optimum values of MgO doses were found to be 1.5-3.0 g/l. The pH valu e ranges are 9.5 to 10 with MgO precipitant and pH of 11.5 to 12 with CaO preci pitant. In the jar experiment the rotation speed, N, 180-200 rpm, (G of 460-480 s ) of mixing for two minutes was the most favorable speed of rapid mixing and th e slow mixing speed of 15-30 rpm, G of (14-35 s ), for twenty minutes gave the best results.At the best operating conditions of the pilot plant, the removal efficien cy of metal ions was more than 97% at doses of MgO (1.0-4.0 g/l).

Removal of Heavy Metals Using Chemicals Precipitation

The effects of superficial gas velocity on heat transfer coefficient and its time-averaged radial profiles along the bed height have been investigated in a pilot-plant scale bubble column of 0.44 m diameter using air–water system. Notable differences were observed in heat transfer coefficients along the bed axial locations particularly between the sparger (Z/D = 0.28) and the fully developed flow (Z/D = 4.8) regions. In the fully developed flow region larger heat transfer coefficient values were obtained compared to those in the sparger region. About 14–22% increase in heat transfer coefficients measured in the fully developed flow region has been observed compared to those measured in the distributor region when the superficial gas velocity increases from 0.05 to 0.45 m/s. The heat transfer coefficients in the column center for all the conditions studied are about 9–13% larger than those near the wall region. It has been noted that in the fully developed flow region, the axial variation of the heat transfer coefficients was not significant.

Heat transfer study in a pilot-plant scale bubble column

Experimental work was carried out to study the effects of hydrodynamic interaction in bubbly two-phase, two-component flow. Experiments were carried out in bubble columns. The neutron transmission technique was used for the measurement of void fraction. Bubble parameters were measured by cross-correlation technique, in addition to a high speed camera. It was found that the drag coefficient of multi-bubbles is a function of void fraction, Reynolds, Weber, Etovos, Morton and Froude numbers. The interaction time was increasing with void fraction.

Experimental investigation of the hydrodynamic interaction in bubbly two-phase flow

Industrial wastewaters from local state textile industry (Al-Khadimia Textile Co.) as well as aqueous prepared solutions of color dyes were subjected to simple physico-chemical treatment. The effect of pollutants concentrations, magnesia and other coagulants doses, filtration rate and the overall run time on the water quality were studied in detail. The treatment involves the addition of either magnesia or lime-water suspensions (combined with CPE) in various doses, 0.1-1.0 g/l to the wastewater and colored samples, to study the effect of varying doses on the treatment efficiency. The optimum values of MgO doses were found to be 0.2-0.4 g/l for synthetic colored. Doses of 0.05-0.2 g/l were the best for industrial wastewater. The removal efficiency of all the pollutants in the different samples increases to more than 95% by increasing the pH values to the range of 9.5 to 10 with MgO coagulant and pH of 11.5 to 12 with CaO coagulant. In the jar experiments the rotation speed, N, of 120-140 rpm, for two minutes was the most favorable speed of coagulation mixing for industrial waters. For flocculation, the mixing speed of 35-40 rpm, (G of 40-45 s -1 ) gave the best removal efficiencies with 20-30 min detention time. At the best operating conditions of the pilot plant, the removal efficiencies of Turbidity, TSS, and color were 97-99%, 94-96%, 94-95%. The TDS removal efficiency was of 39% for Al-Khadimia wastewater.

https://uotechnology.edu.iq/tec_magaz/2013/volum312013/no.04.b.2013/text (7).pdf

Balasim A. Abid

Papers

Removal of lead copper chromium and cobalt ions onto granular activated carbon in batch and fixed-bed adsorbers

Removal of Heavy Metals Using Chemicals Precipitation

Heat transfer study in a pilot-plant scale bubble column

Experimental investigation of the hydrodynamic interaction in bubbly two-phase flow

Color Removal from Industrial Textile Wastewater Using Chemical Adsorption