Causative factors of construction and demolition waste generation in Iraq Construction Industry

The construction industry has hurt the environment from the waste generated during construction activities. Thus, it calls for serious measures to determine the causative factors of construction waste generated. There are limited studies on factors causing construction, and demolition (C&D) waste generation, and these limited studies only focused on the quantification of construction waste. This study took the opportunity to identify the causative factors for the C&D waste generation and also to determine the risk level of each causal factor, and the most important minimization methods to avoiding generating waste. This study was carried out based on the quantitative approach. A total of 39 factors that causes construction waste generation that has been identified from the literature review were considered which were then clustered into 4 groups. Improved questionnaire surveys by 38 construction experts (consultants, contractors and clients) during the pilot study. The actual survey was conducted with a total of 380 questionnaires, received with a response rate of 83.3%. Data analysis was performed using SPSS software. Ranking analysis using the mean score approach found the five most significant causative factors which are poor site management, poor planning, lack of experience, rework and poor controlling. The result also indicated that the majority of the identified factors having a high-risk level, in addition, the better minimization method is environmental awareness. A structural model was developed based on the 4 groups of causative factors using the Partial Least Squared-Structural Equation Modelling (PLS-SEM) technique. It was found that the model fits due to the goodness of fit (GOF ≥ 0.36= 0.658, substantial). Based on the outcome of this study, 39 factors were relevant to the generation of construction and demolition waste in Iraq. These groups of factors should be avoided during construction works to reduce the waste generated. The findings of this study are helpful to authorities and stakeholders in formulating laws and regulations. Furthermore, it provides opportunities for future researchers to conduct additional research’s on the factors that contribute to construction waste generation

Fixed bed adsorption study for removing of reactive orange 16 and acid red 114 dyes from aqueous solution using Kenaf

Kenaf fiber has proved its ability to remove dyes from aqueous solutions. This natural material is characterized by its abundant, relatively low cost and eco-friendly. In this study, kenaf core fiber was modified by adding trimethyl-chloro-bilateral-hydroxypropyl trimethyl ammonium chloride as a quaternizing agent to the constituent in order to increase its ability to adsorb dyes more efficiently. In fixed bed column model, Adsorption experiment was carried out to investigate the effect of height, initial dye concentration, flow rate, and regeneration. Maximum bed capacity, percentage dye removal and equilibrium dye uptake were determined and breakthrough curves were plotted. It was observed that adsorption was higher at lower flow rate, higher bed depth and lower initial dye concentration for two dyes. Maximum bed capacity of 3.25 g was obtained at a flow rate of 10 ml/min, bed height of 7.5 cm and initial dye concentration of 100 ppm. Data from column studies were fitted to three well established column models, Thomas model, Adams-Bohart model and Yoon-Nelson model. The experimental data were in good agreement with theoretical results. The study revealed the applicability of kenaf in fixed bed column for removal of dyes

Adsorption of anionic dye using cationic surfactant - modified kenaf core fibers

Kenaf is a widely cultivated crop, particularly in the tropics. Kenaf core fiber (KCF) is a natural cellulose fiber derived from the plant and it is an important raw material for a variety of products. An attempt was made to chemically quaternized KCF (QKCF) as an adsorbent to increase adsorption affinity towards anionic reactive red-RB dye (RR). KCF was quaternized by treating with (3-chloro-2-hydroxypropyl) trimethylammonium chloride under basic condition. The efficiency of QKCF was investigated by adsorption studies for removing anionic RR dye from aqueous solutions. All experiments were conducted at a batch system and influential parameters cover pH, adsorbent dose, initial dye concentration, agitation speed, temperature, and contact time were investigated. Studies showed that removal efficiency of RR dye increases with increasing the adsorbent dose, agitation speed, temperature, and contact time. The equilibrium data were best represented by the Langmuir isotherm model with maximum adsorption capacity of 169.5 mg/g, and the kinetic data were found to follow the pseudo-second-order kinetic model. In general, QKCF could be suggested as an efficient and low-cost adsorbent for removal anionic dyes

Fixed-bed system for adsorption of anionic acid dyes from binary solution onto quaternized kenaf core fiber

Water pollution due to the effluents from textile industries causes serious concern around the world. During the coloration process, the excess synthetic dyes are discharged into the wastewater stream. In the present research, kenaf core fiber (KCF) residue was chemically modified with (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHPTAC) to alter the surface properties and increase the surface area to develop more active sites that capture anionic dyes from aqueous solution. Fixed-bed adsorption studies were conducted to investigate the performance of using quartenized kenaf core fiber (QKCF) as an adsorbent for the removal of anionic acid dyes from a binary system. The effects of operational parameters, including inlet dye concentration, flow rate, and bed height, were studied in a fixed-bed column system, while other process parameters were fixed, i.e. pH and temperature at 7.5 and 27 ºC, respectively. The fixed-bed column performed better with lower influent dye concentration, less flow rate of the influent, and a higher adsorbent bed depth. Overall, the present study showed that QKCF is a potential adsorbent for anionic dye removal from aqueous solutions in a fixed-bed column system

Batch and fixed bed adsorption study for removal of acid and reactive dyes from aqueous solution using modified kenaf core

The extensive use of commercial activated carbon as an adsorbent for the purification of industrial effluent from textile industry is not economically feasible due its high operational cost. Therefore, this research has been undertaken to explore the potential of certain agro based residues to produce suitable adsorbent. In this research, evaluation of the removal of reactive orange16 (RO16) and acid red 114 (AR114) dyes from aqueous solution was studied in batch and fixed bed column system by using modified kenaf core fibre (MKCF), in which kenaf being one of the agricultural crops used as low-cost adsorbents instead of activated carbon. In this study, kenaf core fibre (KCF) was modified successfully by treating with (3-chloro- 2-hydroxypropyl)- trimethylammonium chloride (CHMAC) as quaternization agent. In batch system, Results showed that the maximum removal of RO16 and AR114 were 97% and 99% respectively. Moreover, the results obtained from the isotherm studies were found to be best fitted with Freundlich isotherm with correlation coefficients (R2 ) of 0.9924 for RO16, and isotherm studies were best fitted with Langmuir isotherm with correlation coefficients (R2 ) 0.9853 for AR114. It was found that the kinetic study followed the pseudo-second-order kinetic model with correlation coefficients R2 =0.9997 and 0.9953 for RO16 and AR114 respectively and the maximum adsorption capacity for RO16 and AR114 were 416.86 mg/g and 238.56 mg/g, respectively. The fixed bed column experiment was carried out by varying the flow rates, initial concentration of the dyes and the height of the bed. experimental data analysis by using three models Thomas, Yoon- Nelson and Adam- Bohart, It was found that the best color removal percentage increased when there was a decrease in the dye concentration, low flow rates and an increase in the bed depth for the both dyes studied. The experimental results have shown a good agreement with the theoretical results. This study showed that the low-cost kenaf fibres could be used for dye removal

Removal of Reactive Orange 16 Dye from Aqueous Solution by Using Modified Kenaf Core Fiber

Evaluated removal of reactive orange 16 (RO16) dye from aqueous solution was studied in batch mode by using kenaf core fiber as low-cost adsorbents. In this attempt, kenaf core fiber with size 0.25–1 mm was treated by using (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHMAC) as quaternization agent. Then effective parameters include adsorbent dose, pH, and contact time and initial dye concentration on adsorption by modified kenaf core fiber was investigated. In addition, isotherms and kinetics adsorption studies were estimated for determination of the equilibrium adsorption capacity and reactions dynamics, respectively. Results showed that the best dose of MKCF was 0.1 g/100 mL, the maximum removal of RO16 was 97.25 at 30°C, pH = 6.5, and agitation speed was 150 rpm. The results also showed that the equilibrium data were represented by Freundlich isotherm with correlation coefficients R2=0.9924, and the kinetic study followed the pseudo-second-order kinetic model with correlation coefficients R2=0.9997 for Co=100 mg/L. Furthermore, the maximum adsorption capacity was 416.86 mg/g. Adsorption through kenaf was found to be very effective for the removal of the RO16 dye