Effect of Curing Temperature on the Properties of Latex Based Membrane for Oily Wastewater Filtration

Oily wastewater pollution has always been part of the most serious worldwide environmental disaster. Thus, the treatment of oily wastewater is notably crucial. In this work, nitrile butadiene rubber/graphene oxide (NBR/GO) membranes were fabricated by latex compounding and curing method which is comparatively brand-new technique to produce membranes for wastewater treatment. Therefore, the steps in the production need to be studied to enhance the performance of the membrane. Curing temperature is an important factor in the production of the latex-based membrane. In this paper, the effect of curing temperature in the range of 90 °C – 110 °C on the morphology, tensile properties, permeation flux, and oil rejection rate performance of the membrane was studied. The curing temperature was found to affect the surface morphology and integrity of the membranes which sequentially affects the performance of the membrane in terms of strength, permeation flux, and oil rejection rate. NBR/GO membranes cured at the temperature of 100 °C exhibit the highest flux of 491.84 L/m2.hr with an oil rejection rate of 95.44 %, with the ultimate tensile strength (UTS), elongation break (EB%), and E-Modulus (E-mod) of 34.490 MPa, 1627.11 %, and 1.309 MPa, respectively.

Preparation of Polystyrene Microsphere-Templated Porous Monolith for Wastewater Filtration

Porous monoliths prepared using templates are highly sought after for filtration applications due to their good mass transport properties and high permeability. Current templates, however, often lead to the formation of dead-end pores and irregular pore distributions, which reduce the efficiency of the substrate flow across the monolith column. This study focused on the preparation of a microsphere-templated porous monolith for wastewater filtration. The optimal template/monomer ratio (50:50, 60:40, 70:30) was determined, and appropriate template removal techniques were assessed for the formation of homogenous pores. The physicochemical characteristics and pore homogeneity of the monoliths were examined. The 60:40 ratio was determined to result in monoliths with homogeneous pore distributions ranging from 1.9 μm to 2.3 μm. SEM and FTIR investigations revealed that solvent treatment was effective for removing templates from the resulting solid monolith. The water quality assessments revealed reductions in the turbidity and the total number of suspended particles in the tested wastewater of up to 96–99%. The findings of this study provide insightful knowledge regarding the fabrication of monoliths with homogenous pores that are beneficial for wastewater treatment.

Valorification of Ulva rigida Algae in Pulp and Paper Industry for Improved Paper Characteristics and Wastewater Heavy Metal Filtration

This paper presents preliminary results on the possibility of incorporating stranded macroalgae into the papermaking process; analyses of the physical-mechanical properties of filter paper, with the addition of stranded macrophytic marine algae from Ulva rigida species obtained previously; results of SEM–EDX analyses of filter paper samples; and results obtained from the filtration of a wastewater from the metallurgical industry, using the improved filter paper samples. In the filter paper recipe, stranded macrophytic seaweed of the species Ulva rigida was added at different percentages of 0.5%, 1%, 2%, 4% and 8%, and the addition was calculated in relation to the absolute dry material. The physicomechanical properties analyzed are grammage, thickness, density, moisture, ash content, breaking load, breaking length, tear resistance, bursting resistance, folding endurance, porosity, smoothness, water absorption and Cobb60 index. Additional information related to the homogeneity of the distribution of elements in the paper mass was obtained by scanning electron microscopy with energy-dispersive X-ray analysis (SEM–EDX). The addition of macroalgae to the paper mass improved the strength characteristics of the paper, such as breaking load, breaking length, tearing resistance, folding endurance and water absorption. Following industrial wastewater filtration using filter paper with added seaweed, positive results were obtained in terms of reduction of total Cr, Cu, total Fe and Zn concentrations.

Development of Environment-Friendly Membrane for Oily Industrial Wastewater Filtration

Latex phase blending and crosslinking method was used in this research work to produce nitrile butadiene rubber-graphene oxide (NBR-GO) membranes. This fabrication technique is new and yields environmentally friendly membranes for oil-water separation. GO loading was varied from 0.5 to 2.0 part per hundred-part rubber (pphr) to study its effect on the performance of NBR-GO membrane. GO was found to alter the surface morphology of the NBR matrix by introducing creases and fold on its surface, which then increases the permeation flux and rejection rate efficiency of the membrane. X-Ray diffraction analysis proves that GO was well dispersed in the membrane due to the non-existence of GO fingerprint diffraction peak at 2θ value of 10–12° in the membrane samples. The membrane filled with 2.0 pphr GO has the capability to permeate 7688.54 Lm−2 h−1 water at operating pressure of 0.3 bar with the corresponding rejection rate of oil recorded at 94.89%. As the GO loading increases from 0.5 to 2.0 pphr, fouling on the membrane surface also increases from Rt value of 45.03% to 87.96%. However, 100% recovery on membrane performance could be achieved by chemical backwashing.

Hydrophilic Surface-Modified PAN Nanofibrous Membranes for Efficient Oil–Water Emulsion Separation

In order to protect the environment, it is important that oily industrial wastewater is degreased before discharging. Membrane filtration is generally preferred for separation of oily wastewater as it does not require any specialised chemical knowledge, and also for its ease of processing, energy efficiency and low maintenance costs. In the present work, hybrid polyacrylonitrile (PAN) nanofibrous membranes were developed for oily wastewater filtration. Membrane surface modification changed nitrile groups on the surface into carboxylic groups, which improve membrane wettability. Subsequently, TiO2 nanoparticles were grafted onto the modified membranes to increase flux and permeability. Following alkaline treatment (NaOH, KOH) of the hydrolysed PAN nanofibres, membrane water permeability increased two- to eight-fold, while TiO2 grafted membrane permeability increase two- to thirteen-fold, compared to unmodified membranes. TiO2 grafted membranes also displayed amphiphilic properties and a decrease in water contact angle from 78.86° to 0°. Our results indicate that modified PAN nanofibrous membranes represent a promising alternative for oily wastewater filtration.

Open pit mine wastewater filtration in the overburden rock debris: case study

Discharge of untreated quarry water into natural water reservoirs is unacceptable for environmental reasons. This circumstance is especially relevant for coal mining regions with a high density of mining enterprises. Treatment of quarry waste water at mining enterprises is a necessary process, provided for in the design documentation. It is due to the significant pollution of quarry water by suspended solids, dissolved salts and organic substances. In addition to expensive sorbents (e.g. zeolite), overburden rocks, confined to the mined area of coal deposit, are used for construction of filtering dams. They are used to construct treatment facilities designed for the entire lifetime of the mining enterprise. Thus, their permeability and purification capacity should be maintained for decades. The movement of filtered water in such massifs is subject to the known laws of filtration. Filtering dams should provide both a free movement of water and the required level of its purification. This is achieved by selecting the appropriate geometry of filter dams (their sizes, base slopes) and the choice of overburden capable of providing the required level of purification in a long and qualitative term. The article presents the results of studies of the geometry of the filtering massif and the methodology of selection of overburden used for the construction of filtering dams.