Bench-Scale Fixed-Bed Column Study for the Removal of Dye-Contaminated Effluent Using Sewage-Sludge-Based Biochar

Batik industrial effluent wastewater (BIE) contains toxic dyes that, if directly channeled into receiving water bodies without proper treatment, could pollute the aquatic ecosystem and, detrimentally, affect the health of people. This study is aimed at assessing the adsorptive efficacy of a novel low-cost sewage-sludge-based biochar (SSB), in removing color from batik industrial effluent (BIE). Sewage-sludge-based biochar (SSB) was synthesized through two stages, the first is raw-material gathering and preparation. The second stage is carbonization, in a muffle furnace, at 700 ◦C for 60 min. To investigate the changes introduced by the preparation process, the raw sewage sludge (RS) and SSB were characterized by the Brunauer–Emmett–Teller (BET) method, Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy. The surface area of biochar was found to be 117.7 m2/g. The results of FTIR showed that some functional groups, such as CO and OH, were hosted on the surface of the biochar. Continuous fixed-bed column studies were conducted, by using SSB as an adsorbent. A glass column with a diameter of 20 mm was packed with SSB, to depths of 5 cm, 8 cm, and 12 cm. The volumes of BIE passing through the column were 384 mL/d, 864 mL/d, and 1680 mL/d, at a flow rate of 16 mL/h, 36 mL/h, and 70 mL/h, respectively. The initial color concentration in the batik sample was 234 Pt-Co, and the pH was kept in the range of 3–5. The effect of varying bed depth and flow rate over time on the removal efficiency of color was analyzed. It was observed that the breakthrough time differed according to the depth of the bed and changes in the flow rates. The longest time, where breakthrough and exhausting points occurred, was recorded at the highest bed and slowest flowrate. However, the increase in flow rate and decrease in bed depth made the breakthrough curves steeper. The maximum bed capacity of 42.30 mg/g was achieved at a 16 mL/h flowrate and 12 cm bed height. Thomas and Bohart–Adams mathematical models were applied, to analyze the adsorption data and the interaction between the adsorption variables. For both models, the correlation coefficient (R 2 ) was more than 0.9, which signifies that the experimental data are well fitted. Furthermore, the adsorption behavior is best explained by the Thomas model, as it covers the whole range of breakthrough curves

FLEXURAL BEHAVIOUR OF HIGH-PERFORMANCE FIBRE REINFORCED COMPOSITE-FILLED DOUBLE SKIN STEEL TUBE BEAMS WRAPPED CARBON FIBRE REINFORCED POLYMER SHEETS

Concrete filled-double skin steel tube (CFDST) members provide economic benefits by reducing self-weight, avoiding formwork and reinforcement bars as required in the traditional steel or concrete constructio

Flexural Behavior of Double-Skin Steel Tube Beams Filled with Fiber-Reinforced Cementitious Composite and Strengthened with CFRP Sheets

The concrete-filled double skin steel tube (CFDST) is a more viable option compared to a concrete-filled steel tube (CFST) due to consisting a hollow section, while degradation is enhanced simply by using carbon fiber-reinforced polymer (CFRP). Hence, the stabilization of a concrete’s ductile strength needs high- performance fiber-reinforced cementitious conmposite. This study investigates the behavior of high-performance fiber-reinforced cementitious composite-filled double-skin steel tube (HPCFDST) beams strengthened longitudinally with various layers, lengths, and configurtion of CFRP sheets. The findings showed that, with increased CFRP layers, the moment capacity and flexural stiffness values of the retrofitted HPCFDST beams have significantly improved. For an instant, the moment capacity of HPCFDST beams improved by approximately 28.5% and 32.6% when they were wrapped partially along 100% with two and three layers, respectively, compared to the control beam. Moreover, the moment capacity of the HPCFDST beam using two partial layers of CFRP along 75% of its sufficient length was closed to the findings of the beam with two full CFRP layers. For energy absorption, the results showed a vast disparity. Only the two layers with a 100% full length and partial wrapping showed increasing performance over the control. Furthermore, the typical failure mode of HPCFDST beams was observed to be local buckling at the top surface near the point of loading and CFRP rapture at the bottom of effect length

Phenol removal from aqueous solutions using rice stalk-derived activated carbon: Equilibrium, kinetics, and thermodynamics study

The conventional disposal practices of rice stalks (RS) such as burning in situ or incorporating in the soil, contribute to climate change and endanger the long-term soil fertility. This study investigated the production of activated carbon (AC) using rice stalks as a sustainable recycling solution. The rice stalks (RS) were carbonized in a tube furnace at 500 °C and heating rate of 10 °C/min for 2 h. The rice stalks-based activated carbon (RSA) properties were analyzed based on Brunauer-Emmett-Teller (BET) technique to measure the surface area and transform infrared spectroscopy (FTIR) measurements to identify the surface functional groups. RSA was also characterized using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-Ray spectroscopy (SEM-EDX). Batch experiments were conducted to examine the efficiency of RSA in removing phenol, with varying operation parameters comprising pH (2–9), initial phenol concentration (IPC) (50–200 mg/L), reaction time (5–300 min), and RSA dose (0.2–2 g/100 ml). The surface area (SBET) of RSA was 488.26 m2/g with a total micropore volume of 0.165 cm³/g, and a pore diameter of 6.99 nm. The highest phenol uptake of RSA was 80.37 mg/g. The kinetics of phenol adsorption was found to be accurately described by the pseudo-second-order reaction, while the Langmuir model provided a better match for the isotherm process than the Freundlich model. The thermodynamic study indicated that the adsorption process was exothermic and spontaneous. These results confirm that the adsorption process occurred due to physical forces, rather than involving chemical bonding, providing further insight into the underlying mechanisms

Sustainable sewage sludge biosorbent activated carbon for remediation of heavy metals: Optimization by response surface methodology

This study investigated the potential use of sewage sludge-based activated carbon in the removal of copper (Cu) and cadmium (Cd) ions from aqueous solutions. The activated carbon (AC) was prepared by chemical activation using potassium hydroxide KOH and heating in a tube furnace at 600 °C for 2 h. The produced activated carbon was further subject to a sulfurization process to enhance its removal efficiency. The study used Box-Behnken Design (BBD) in response surface methodology (RSM) to optimize several parameters, including initial metal concentration, activated carbon dose, pH, and contact time. Results showed that the sulfurization process introduced sulfur functional groups (SO) to the surface of the activated carbon and decreased its specific area from 190 to 173 m2/g. The quadratic model was suggested as the best model to describe the effect of the adsorption parameters on the removal percentage with high R2 values (≥0.9) and p-value less than 0.05. Second-order polynomial equations, analysis of variance (ANOVA), and three-dimensional surface plots were developed to assess the interaction between the parameters and the optimal conditions to remove copper and cadmium ions. The optimum removal parameters for copper ions were 300 min, 100 ppm initial concentration, 20 g/L activated carbon dose, and pH 6, with a removal efficiency of 83.9%. Cadmium removal of 87.5% was achieved at 11 ppm, 300 minutes contact time, pH 6, and 2.5 g/L adsorbent dose. The activated carbon capacity in removing copper and cadmium was 16 mg/g and 17.6 mg/g respectively. The sulfurization process increased the removal percentage for copper and cadmium ions by 14.5 and 18.7% respectively. Advanced analytical techniques such as FITR, SEM-EDX, BET surface area, and elemental analysis were used to characterize the materials

Beneficial Effects of 3D BIM for Pre-Empting Waste during the Planning and Design Stage of Building and Waste Reduction Strategies

The use of various tools for construction waste management throughout the planning and design (P&D) stage has several advantages. According to some research, building information modelling, or BIM, could be a valuable tool for predicting waste. This paper discusses how BIM could be used for pre-empting waste and reducing the course of the planning and design process of constructing a building. In Malaysia, a questionnaire survey of 340 construction experts was undertaken. Simultaneously, a regression analysis was carried out in order to determine the impact of BIM on the management of construction waste during the planning and design stage. This research could help many stakeholders in the construction industry to recognise various aspects of waste management, beginning with the planning and design stage of a project, which can be represented by designing a model that can be applied to mitigate waste during the construction of a building

Beneficial Effects of 3D BIM for Pre-Empting Waste during the Planning and Design Stage of Building and Waste Reduction Strategies

The use of various tools for construction waste management throughout the planning and design (P&D) stage has several advantages. According to some research, building information modelling, or BIM, could be a valuable tool for predicting waste. This paper discusses how BIM could be used for pre-empting waste and reducing the course of the planning and design process of constructing a building. In Malaysia, a questionnaire survey of 340 construction experts was undertaken. Simultaneously, a regression analysis was carried out in order to determine the impact of BIM on the management of construction waste during the planning and design stage. This research could help many stakeholders in the construction industry to recognise various aspects of waste management, beginning with the planning and design stage of a project, which can be represented by designing a model that can be applied to mitigate waste during the construction of a building

Adsorptive Removal of Boron by DIAION™ CRB05: Characterization, Kinetics, Isotherm, and Optimization by Response Surface Methodology

A significant issue for the ecosystem is the presence of boron in water resources, particularly in produced water. Batch and dynamic experiments were used in this research to extract boron in the form of boric acid from aqueous solutions using boron selective resins, DIAION CRB05. DIAION™ CRB05 is an adsorbent that is effective in extracting boron from aqueous solutions due to its high binding capacity and selectivity for boron ions, and it is also regenerable, making it cost-effective and sustainable. Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), and FTIR analysis for DIAION CRB05 characterization. To increase the adsorption capacity and find the ideal values for predictor variables such as pH, adsorbent dose, time, and boric acid concentration, the Box–Behnken response surface method (RSM) was applied. The dosage was reported to be 2000 mg/L at pH 2 and boron initial concentration of 1115 mg/L with 255 min for the highest removal anticipated from RSM. According to the outcomes of this research, the DIAION CRB05 material enhanced boron removal capability and has superior performance to several currently available adsorbents, which makes it suitable for use as an adsorbent for removing boric acid from aqueous solutions. The outcomes of isotherm and kinetic experiments were fitted using linear methods. The Temkin isotherm and the pseudo-first-order model were found to have good fits after comparison with R2 of 0.998, and 0.997, respectively. The results of the study demonstrate the effectiveness of DIAION™ CRB05 in removing boron from aqueous solutions and provide insight into the optimal conditions for the adsorption process. Thus, the DIAION CRB05 resin was chosen as the ideal choice for recovering boron from an aqueous solution because of its higher sorption capacity and percentage of boron absorbed