Low-cost Waste Material Research Articles

Potentiality of waste human hair towards removal of chromium(VI) from solution: kinetic and equilibrium studies

Industrial and agricultural activities discharges huge amount of hazardous pollutants that lead to massive environmental pollution and health hazards. Keratin is a fascinating protein and useful biopolymer, which is usually found in wool, human hair, nails, feathers, etc. The present research deals with the potentiality of human hair towards removal of hexavalent chromium from aqueous solution through batch mode. The adsorbent was characterized by pHZPC and SEM study. The Cr(VI) adsorption was studied with the help of different process parameters, viz. initial concentration, contact time, adsorbent dose, pH, and temperature. Results revealed that Cr(VI) adsorption by human hair was highly pH sensitive. Maximum Cr(VI) was adsorbed from water at pH 1.0. Study of temperature effect on chromium adsorption confirmed the endothermic behaviour of the process. On the other hand, thermodynamic properties were also calculated and found that physisorption was dominant with activation energy of 0.385 kJ mol−1. Kinetic study revealed that pseudo-second-order model was followed by the adsorption process. Adsorption equilibrium was analysed with Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models. Results showed that the adsorption system followed both Langmuir and Freundlich isotherms with Langmuir adsorption capacity of 9.852 mg g−1, which was compared with other adsorbents and observed that the performance of the present adsorbent is better than others. Finally, it can be concluded that human hair could be an alternative chief low-cost waste material for decontamination of heavy metals from an aqueous medium.

Photocatalytic hydrogen production over mixed Cd-Zn sulfide catalysts promoted with nickel or nickel phosphide

Abstract Photocatalytic production of hydrogen has been investigated over irradiated aqueous dispersions of mixed Cd-Zn sulfide catalysts (CZS) promoted with nickel or nickel phosphide in the presence of sulfide/sulfite ions as sacrificial electron donors. The CZS composites were prepared by a co-precipitation method followed by calcination in air at temperatures in the range of 300 to 600 °C. It has been found that heat treatment at 500 °C results in materials with increased activity for H2 evolution, which is attributed to the formation of the Zn0.78Cd0.22S phase. Photocatalytic performance of CZS(500) is further improved following addition of small amounts of Ni or Ni2P on the photocatalyst surface. The activity of the optimized materials, loaded with 0.05 wt.% Ni or 0.25 wt.% Ni2P, exhibit similar activity with a Pt-promoted CZS(500) catalyst, and is one order of magnitude higher than that of the reference TiO2 catalyst of the same platinum loading (0.25 wt.% Pt). Results of long-term stability tests show that the 0.25%Ni2P/CZS(500) catalyst is very stable in the presence of S2−/SO32− ions in solution, with cadmium leaching not exceeding 0.1% after 65 h under irradiation. Experiments performed with the use of low (or negative) cost waste materials, such as real wastewater resulting from film printing processes or glycerol solutions, demonstrate that the 0.25%Ni2P/CZS(500) photocatalyst exhibits stable H2 evolution even in the absence of S2−/SO32− ions and has the potential to be used as a solar light-responsive photocatalyst for practical applications.

Enhancing mortar strengths by ternary geopolymer binder of metakaolin, slag, and palm ash

PurposeThe purpose of this paper is to develop an alternative new ternary geopolymer mortar (MKSP) to resolve a traditional mortar problem which exhibits several disadvantages, including poor strengths and surface microcracks and the CO2 air pollution.Design/methodology/approachThe MKSP ternary binder was produced using metakaolin (MK), slag (S), and palm oil fuel ash (POFA) activated with an alkaline mixture of sodium silicate (Na2SiO3) and 10 M NaOH in a mass ratio of 2.5. Seven different mix proportions of MK, slag, and POFA were used to fabricate MKSP mortars. The water-to-binder ratio was varied between 0.4 and 0.5. The mortars were heat cured for 2 h at 80°C and then aged in air. Flexural stress and strain, mortars flow and compressive strength were tested. Furthermore, the mortars were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analyses.FindingsThe results showed that the sample MKSP6, which contained 40 percent MK, 40 percent slag, and 20 percent POFA, exhibited high compressive strength (52 MPa) without any cracks and flexural strength (6.9 MPa) at 28 days after being cured for 2 h at 80°C; however, the MKSP7 mortar with optimal strength of 55 MPa showed some surface cracks . Further, the results of the XRD, SEM, and FTIR analyses indicated that the MKSP mortars primarily consisted of a crystalline (Si+Al) phase (70 percent) and a smaller amorphous (Si+Ca) phase (30 percent).Research limitations/implicationsThe MKSP ternary geopolymer mix has three limitations as an importance of heat curing for development early strength, POFA content less than 20 percent to gain high normal strength and delaying the sitting time by controlling the slag content or the alkali activator type.Practical implicationsThe use of geopolymer materials binder in a real building is limited and it still under research, Thus, the first model of real applied geopolymer cement in 2008 was the E-Crete model that formed by Zeobond company Australia to take the technology of geopolymer concrete to reality. Zeobond Pty Ltd was founded by Professor Jannie S.J. van (van Deventer et al., 2013), it was used to product precast concrete for the building structure. The second model was PYRAMENT model in 2002 by American cement manufacturer Lone Star Industries which was produced from the development carried out on inorganic alumino-silicate polymers called geopolymer (Palomo et al., 1999). In 2013 the third model was Queensland’s University GCI building with three suspended floors made from structural geopolymer concrete containing slag/fly ash-based geopolymer (Pathak, 2016). In Australia, 2014, the newly completed Brisbane West Wellcamp airport becomes the greenest airport in the world. Cement-free geopolymer concrete was used to save more than 6,600 tons of carbon emissions in the construction of the airport. Therefore, the next century will see cement companies developing alternative binders that are more environmentally friendly from a sustainable development point of view.Originality/valueProduction of new geopolymer binder of mortar as alternative to traditional cement binder with high early and normal strength from low cost waste materials, less potential of cracking, less energy consumption need and low carbon dioxide emission.

Composite Superabsorbent Hydrogel of Acrylic Copolymer and Eggshell: Effect of Biofiller Addition

Eggshell (ES) is an abundant waste material which is mainly composed of calcium carbonate. A superabsorbent hydrogel composite based on poly(acrylamide-co-potassium acrylate) as matrix containing 17 wt.% of chicken ES powder as a filler was synthesized and compared with the gel without filler. The characterization was carried out by Fourier transform infrared (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), rheological analysis and kinetics studies. The dispersion of ES in the polymeric matrix was homogeneous. The interaction between the acrylate and calcium cation was detected by FTIR analysis. The composite improved the gel strength and the absorption of water and saline solution increased by 100 and 41%, respectively. The high values for the swelling, the homogeneous structure and the good mechanical properties obtained with the incorporation of a relatively high content of a low-cost waste material indicate that this composite is suitable for application in the agriculture. In addition, this approach provides a more ecologically sound and useful destination for eggshell residue.

Equilibrium and Kinetic Studies of Adsorption of Lead using Low Cost Adsorbents

Background: Anthropogenic activities are major source of water pollution, particularly, because of haphazard dumping of heavy metals which get accumulated through trophic levels posing a severe risk to the surroundings. The removal of heavy metals from wastewater is, thus, very significant. Objective: The objective of the present study is to use rice husk, tea waste and orange peel for removal of Pb (II) ions by adsorption and to develop equilibrium and kinetic studies data for the same. Method: The batch process of adsorption was used and the concentration of lead adsorbed was measured titrimetrically. Findings: The maximum removal efficiency has been observed as 88% in tea waste and 80% in rice husk and orange peel. The equilibrium data obtained at optimized conditions for all the metal ions studied has been subjected to the isotherm models used for adsorption, namely, Langmuir and Freundlich. Further, to examine the kinetics for adsorption of Pb (II) ions on the adsorbents under study, pseudo first order and second order equations have been analysed. Thus, it was concluded that the utilization of low cost waste materials for treating wastewater using adsorption is effective, ecofriendly, locally available causing no pollution along with solving the problem of waste disposal.

Application of waste materials as potential biosorbents for Cu(II) and Zn(II) removal

Mining is probably the most common activity that fundamentally impacts the country. The problems connected with the extraction of sulphide ores arise especially during the final stage of mining, closure and abandonment of the extraction area, when the conditions for the generation of strong acid water are most likely to occur. With respect to the diversity of compounds in acid mine drainage (AMD) and its low pH values it is hard to find an effective and inexpensive “active” treatment process. Recently, numerous approaches have been studied for the development of cheaper and more effective technologies, both to decrease the amount of heavy metals and to improve the quality of the treated effluent. Adsorption has become one of the alternative treatments; in the recent years, the search for low-cost adsorbents that have metal-binding capacities has intensified. Adsorption of heavy metals (Cu and Zn) from single-component aqueous solutions onto non-modified poplar sawdust, hemp shives and peat has been studied using the batch-adsorption techniques. For this purpose, solutions with different concentrations ranging from 10 to 150 mg/L have been used. The study was carried out to examine the adsorption capacity of the low-cost waste materials as potential biosorbents for the removal of heavy metals from acid mine drainage. The adsorption isotherms could be better fitted by the Langmuir model (values of the correlation factor range from 0.974 to 0.997). The values of the separation factor (RL) in the present study were found to be within 0.037–0.728, indicating the favorable adsorption process. From the comparison of maximum sorption capacities, it is evident that the best adsorption properties are exhibited by the hemp shives, and copper is overall better adsorbed than zinc (Qmax = 12.84 mg/g and 8.28 mg/g for copper and zinc, respectively). The results indicate that these freely abundant, low-cost waste materials can be treated as economically viable for the removal of metal ions in acidic conditions.DOI: http://dx.doi.org/10.5755/j01.ct.67.1.15003

Removal of Pb, Cd, and Cr in a water purification system using modified mineral waste materials and activated carbon derived from waste materials

This study attempts to find out and optimize the removal efficiency of heavy metals in a water purification unit using a low-cost waste material and modified mineral waste materials (MMWM) accompanied with activated carbon (AC) derived from waste materials. The factors of the inner diameter of the purification unit (2.6-5cm), the height of the packing materials (5-20cm), the size of AC (200-20mesh), the size of MMWM (1-0.045mm), and the ratio between AC and MMWM in the packing materials (1:0 - 0:1) were examined based on a L18 (5) 3 orthogonal array design. In order to achieve an optimally maximum removal efficiency, the factors of the inner diameter of the purification unit (2.6-7.5cm), the height of the packing materials (10-30cm), and the ratio between AC and MMWM in the packing materials (1:4-4:1) were examined based on a L16 (4) 3 orthogonal array design. A height of 25cm, inner diameter of 5cm, ratio between AC and MMWM of 3:2 with size of 60-40mesh and 0.075-0.045mm, respectively, were the best conditions determined by the ICP-OES analysis to perform the adsorption of heavy metals in this study.

Outdoors in Preschool Teaching: A Model Implementation in Turkey

<p>In the research, an explanatory case study was carried out which is a kind of qualitative research. By presenting a model implementation, how to create outdoor centers and teachers’ views on the designed model are introduced with the purpose of making a contribution to teachers and preschool education institutions. Within this framework, by receiving opinions of teachers, an outdoor space design was made, and by the end of a 2 month work, 12 centers (art, music, playing house, writing, balance, eye-hand coordination, vegetable, fruit, book, performance, sensory) were created in the garden of research and application kindergarten of a university. After 6 teachers used the design in the 2 month education period, their opinions are received. Teachers expressed the efficiency of center designs in the garden in terms of supporting children’s development and implementing educational programs. Model implementation was described in detail and was discussed with the related body of literature. A design was made regarding how center implementation which will support children development in the best way can be formed using low-cost waste and natural material. The model is thought to raise awareness about putting outdoor space in good use.</p>

Preparation and evaluation of hydrogel composites based on starch-g-PNaMA/eggshell particles as dye biosorbent

In this study, eggshell (ES) particles as an available and low-cost waste material were used for preparing hydrogel composites as dye biosorbents. For this purpose, hydrogel composites were prepared through free-radical graft copolymerization of wheat starch and sodium methacrylate (NaMA) in the presence of different contents of ES particles with various size ranges. FTIR spectroscopy confirmed graft copolymerization of NaMA moieties onto starch backbone besides the combination of ES particles with the starch-g-PNaMA matrix. The gel content values were high (>99%), which showed proper graft efficiency for hydrogel composites. Incorporation of ES particles into hydrogel matrix resulted in faster water absorption at initial stage and lower equilibrium water absorption capacity. Addition of 60% ES particles into starch-g-PNaMA provided a cost-effective adsorbent with similar CV adsorption capacity compared to unfilled hydrogel, while MB removal was slightly decreased. The dye adsorption by hydrogel composites followed the pseudo-second-order kinetics, indicating that chemical sorption is the rate-limiting step.

Small domestic wastewater treatment using waste materials

Phosphorus pollution of groundwater from small wastewater system is often considered as a major threat for aquatic habitats. Recirculating biofilters are often used to treat small wastewater systems without significant removal of phosphorus. In this paper, a low-cost waste material (dried alum residual) in pre-treated effluents from recirculating biofilters was examined. Two different types of wastewater were used; one collected from a pilot scale biofilter from a municipality and the other generated in the laboratory using bench scale biofilter. Sorption-based treatment system was used to remove phosphorus using alum residual. Batch and fixed bed column tests were conducted. Results indicated that alum residual was effective in removing phosphorus. The presence of organic matter (BOD5) showed to have decreased the phosphorus sorption behaviour. The leaching of aluminium was reasonable and in many cases aluminium was adsorbed onto the alum residual.

Bioremoval of arsenite and sulfate by a mixed culture with sulfate-reducing capacity growing on powdered chicken feathers

A relatively unusual and low-cost waste material was investigated for As(III) and SO42− removal by a mixed culture containing sulfate-reducing bacteria (SRB). Powdered chicken feathers (PCF) were tested as an organic nutrient source for SRB growth and also as solid support for As(III) immobilization. PCF's efficiency as a growth substrate was compared with that of sodium lactate, used as a positive control. As(III) removal increased, from 38% (in the presence of sodium lactate only) to 80%, in the presence of PCF and sodium lactate together. The soluble organic part of PCF contained 2302mgL−1 of carbon, suggesting the possibility of using PCF as an electron donor for SRB growth. When PCF was the only carbon source, the achieved sulfate removal was lower (13.4%) than that observed when PCF and lactate were added to the medium (27.0%), but higher than those obtained when only lactate was employed at COD/sulfate ratios of 0.67 or 1. Arsenic removal increased from 38% (lactate, COD/sulfate=0.67) to 80% in the presence of PCF and lactate. The results suggest an alternative biological route for arsenite removal which does not require the use of a strong oxidizing agent to promote As(III) oxidation to As(V) before its removal.

Phenol removal from aqueous phase by adsorption on activated carbon prepared from paper mill sludge

A new activated carbon was synthesized using paper mill sludge as a low cost waste material. It was employed to remove phenol from aqueous solution in the concentration range of 0–60 mg/l and temperature range of 25–45°C. The adsorbent characteristics were determined by different analyses such as BET, FTIR, and SEM. The effects of pH, adsorbent dosage, initial phenol concentration, contact time, and temperature on phenol adsorption were investigated. The maximum adsorption capacity of 15.04 mg/g was obtained at optimum condition. The equilibrium experimental data were analyzed by several model isotherms. The best-fitted adsorption models were found to be in the order: Langmuir–Freundlich > Freundlich > Langmuir. The kinetics of phenol adsorption was investigated using different kinetics models. Experimental kinetic data were well described by the pseudo-second-order model. It was found that the temperature had negative impact on the phenol removal. Thermodynamic parameters such as Gibbs free energy, the enthalpy, and the entropy changes were determined. The results indicated that phenol adsorption process was spontaneous, exothermic, and controlled by physical sorption mechanism. Finally, the results revealed that the paper mill sludge can be employed as a promising raw material in terms of economical and technical aspects for the removal of contaminants from wastewaters.

Solid–liquid two-phase partitioning bioreactors (TPPBs) operated with waste polymers. Case study: 2,4-dichlorophenol biodegradation with used automobile tires as the partitioning phase

Used automobile tire pieces were tested for their suitability as the sequestering phase in a two-phase partitioning bioreactor to treat 2,4-dichlorophenol (DCP). Abiotic sorption tests and equilibrium partitioning tests confirmed that tire "crumble" possesses very favourable properties for this application with DCP diffusivity (4.8×10(-8)cm(2)/s) and partition coefficient (31) values comparable to those of commercially available polymers. Biodegradation tests further validated the effectiveness of using waste tires to detoxify a DCP solution, and allow for enhanced biodegradation compared to conventional single-phase operation. These results establish the potential of using a low-cost waste material to assist in the bioremediation of a toxic aqueous contaminant.

Using the Low-Cost Waste Materials for Heavy Metals Removal from the Mine Wastewater

The possibility of application of low-cost and easily available materials such as cardboard or sawdust for the heavy metals removal from the acid mine water was investigated. The sawdust was obtained from oak and fir-wood. Those materials were tested on the real acid mine wastewater that contained copper, iron, zinc, nickel, and manganese in the concentrations above the maximal allowed level. The adsorption degrees of those elements were investigated. The results were shown that the iron was mechanically removed. The results of chemical analysis of effluent obtained by the use of sawdust from fir-wood indicate that the values for iron and nickel ions were lower than allowed values by the legislative direction. The highest value for copper adsorption degree of 98.31% was achieved at pH value of 7.94. Content of manganese in the effluent and at the end of process, was near the initial value. Using the sawdust obtained from oak as the adsorption material, zinc and manganese concentration in the effluent was near the start values and copper and iron content was decreased but the values were higher than allowed.Using the cardboard, the copper adsorption degree was up to 95 mass%, iron content was under the limit value for the applied chemical detection method. The content of the manganese was not changed and the content of the zinc was decreased but the concentration was over the maximum allowed value.

The potential of compost-based biobarriers for Cr(VI) removal from contaminated groundwater: Column test

This paper presents the results of a column reactor test, aiming at evaluating the performance of a biological permeable barrier made of low-cost waste materials, for Cr(VI) removal from contaminated groundwater. A 1:1 by volume mixture of green compost and siliceous gravel was tested as reactive medium in the experimental activity. A 10 mg/l Cr(VI) contaminated solution was used and the residual Cr(VI) concentration along the column height and in the outlet was determined in the water samples collected daily. Also pH, redox potential and COD were analyzed. At the end of the test, the reactive medium was characterized in terms of Cr(VI) and total chromium. The Cr(VI) removal efficiency was higher than 99% during the entire experimental activity. The influence of the biological activity on Cr(VI) removal efficiency was evaluated by varying the organic carbon and nitrogen dosages in the contaminated solution fed to the system; a removal decrease was observed when the organic carbon was not enough to sustain the microbial metabolism. The Cr(VI) removal was strictly linked to the biological activity of the native biomass of compost. No Cr(III) was detected in the outlet: the Cr(III) produced was entrapped in the solid matrix. Two main processes involved were: adsorption on the organic-based matrix and reduction into Cr(III) mediated by the anaerobic microbial metabolism of the bacteria residing in green compost. Siliceous gravel was used as the structure matrix, since its contribution to the removal was almost negligible. Thanks to the proven efficiency and to the low-cost, the reactive medium used can represent a valid alternative to conventional approaches to chromium remediation.

Reprocessing and Reuse of Waste Tire Rubber to Solve Air-Quality Related Problems

There is a potential for using waste tire rubber to make activated-carbon adsorbents for air-quality control applications. Such an approach provides a recycling path for waste tires and the production of new adsorbents from a low-cost waste material. Tire-derived activated carbons (TDACs) were prepared from waste tires. The resulting products are generally mesoporous, with N2−BET specific surface areas ranging from 239 to 1031 m2/g. TDACs were tested for their ability to store natural gas and remove organic compounds and mercury species from gas streams. TDACs are able to achieve 36% of the recommended adsorbed natural gas (methane) storage capacity for natural-gas-fueled vehicles. Equilibrium adsorption capacities for CH4 achieved by TDACs are comparable to Calgon BPL, a commercially available activated-carbon adsorbent. The acetone adsorption capacity for a TDAC is 67% of the adsorption capacity achieved by BPL at 1 vol % acetone. Adsorption capacities of mercury in simulated flue-gas streams are, in ge...

Removal of coloured organic matter by adsorption onto low-cost waste materials

Twelve different adsorbents, originating from waste materials, were used to treat an effluent, of complex composition, from a chemical works. The effectiveness of each adsorbent was measured in terms of its effect on the colour (absorbance at 450 nm) and COD levels of the effluent and also in terms of its adsorption capacity towards individual constituents of the effluent. The results showed that all adsorbents would physically adsorb constituents in reversible processes. Some constituents were more readily adsorbed than others. This meant that little correlation was observed between changes to the colour and COD levels of the effluent, because individual constituents made different contributions to these properties. The problem is further complicated by adsorbents, particularly those which had not been processed, contributing new constituents to the effluent. Thermodynamic data obtained from this study were used to predict the relative distribution of three constituents on the surface of different adsorbents. These results suggest that, for this effluent, adsorption onto waste material would be most effectively applied by using it in combination with other removal techniques.