A high quality activated carbon has been obtained, by physical activation with steam, from a Moroccan agricultural by-product (Argan shells) and their characteristics were investigated. In order to optimize experimental conditions of the preparation, a combination of a fractional factorial design and a Doehlert design was applied. In the first step of this work, a two-level fractional factorial design 2(5–1) was used to study effects and first order interactions of various factors such as atmosphere in carbonization step, carbonization time at 400 °C, activation temperature, activation time and steam flow. The results reveal that the most influential factors on the yield and the methylene blue adsorption are activation temperature, activation time, steam flow and the presence of a significant interaction between activation temperature and activation time in both cases. In the second step, activation temperature and activation time were optimized using Response Surface Methodology with a Doehlert design, and Desirability function. The optimal conditions for the preparation of activated carbon have been identified to be an activation temperature of 880 °C, an activation time of 96 min and steam flow fixed at this positive level of 0.2 cm3 min− 1. The characteristics of prepared activated carbon obtained at the optimal conditions were determined using adsorption capacity of methylene blue, iodine and phenol, BET surface area, pHpzc, and surface functions based on Boehm method. Those characteristics (MB adsorption: 608.9 mg g− 1, iodine adsorption: 1026.4 mg g− 1, phenol adsorption: 633.3 mg g− 1, BET surface area: 1292 m2 g− 1) were shown greater than those of a commercial activated carbon used in water treatment and those reported by other researchers studying activated carbon preparation from various solid wastes by steam activation method.
On the other hand, this work showed that Argan shells are a good precursor for the production of activated carbon, by steam physical activation, with high performance to be used in water treatment applications.
Chemometrics and Intelligent Laboratory Systems 12/2014; 139:48–57. DOI:10.1016/j.chemolab.2014.09.006 · 2.38 Impact Factor
In this study, activated carbons were prepared from oil palm shells by physicochemical activation. The methodology of experimental design was used to optimize the preparation conditions. The influences of the impregnation ratio (0.6–3.4) and the activation temperature between 601°C and 799°C on the following three responses: activated carbon yield (R/AC-), the iodine adsorption (/AC-), and the methylene blue adsorption (MB/AC-) results were investigated using analysis of variance (ANOVA) to identify the significant parameters. Under the experimental conditions investigated, the activation temperature of 770°C and impregnation ratio of 2/1 leading to the R/AC- of 52.10%, the /AC- of 697.86 mg/g, and the MB/AC- of 346.25 mg/g were found to be optimum conditions for producing activated carbon with well compromise of desirability. The two factors had both synergetic and antagonistic effects on the three responses studied. The micrographs of activated carbons examined with scanning electron microscopy revealed that the activated carbons were found to be mainly microporous and mesoporous.
11/2012; 2013. DOI:10.1155/2013/654343
The present work is aimed to study the feasibility of reuse of sludge hydroxides obtained during the
treatment processes of coagulation / flocculation / sedimentation in the drinkingwater treatment
plants. The reuse of sludge in situ, as an additive to conventional coagulant aluminum sulfate, has
two advantages: economical recycling of substances coagulant contained in the sludge and the
reduction of environmental impact generated by their disposal into the environment without any
Design of Experiment (DOE) was used to set up optimal designs that combine mixture components,
such as aluminum sulfate (AS) and Fresh sludge (BF) and process factors that are the charge of
water (C), the dose of reagents coagulants (D) and the concentration of polyelectrolyte (E) as
The responses studied were reduction in turbidity (Y1), mass of sludge generated after processing
(Y2) and aluminum concentration in treated water (Y3).
The main results show that:
• The model validation based on comparison tests showed that experimental results and those
predicted by the model are close.
• The mixture corresponding to the formulation (75% of Aluminum Sulfate and 25% of Fresh
sludge has achieved a reduction of turbidity of about 97% with an amount of sludge formed
less than 1 g/L and an aluminum concentration less than 1 mg/L, values close to those
obtained with aluminum sulphate alone.
• The economic study showed that the application of this solution will generate annual
savings in terms of processing reagents estimated at 1million DH.
Case Study at the 4th European DOE User Meeting in Vienna, Vienna; 05/2012
A series of seven activated carbons was obtained for use in drinking water treatments by steam-activation of olive-waste cakes. This raw material is an abundant and cheap waste byproduct of oil production, making these activated carbons economically feasible. The activated carbons, prepared by the one step method, were characterized, and the evolution of their characteristics (yield, adsorption capacities, and porosity) was analyzed as a function of the experimental parameters (activation temperature and activation time), using the Doehlert matrix. The Doehlert matrix allows the response surface to be studied with a good quality parameter estimation of the quadratic model. Each response has been described by a second order model that was adequate to predict responses in all experimental regions. The coefficients of the postulated model were calculated from the experimental responses by means of least squares regression, using the NEMROD software. We determined the region in which the optimum values of both activation temperature and activation time were achieved for the preparation of activated carbons suitable for use in water treatments. The "optimal activated carbon" was experimentally obtained, and its characteristic parameters showed a good agreement with those calculated from the model. The results obtained for activated carbons prepared by the one-step method were compared with those for activated carbons prepared by the two-step method. The characteristics of activated carbons obtained by the one-step and two-step methods showed that "one-step" activated carbons have a highly developed porous texture formed mainly of large macropores and micropores, whereas "two-step" activated carbons have a predominance of mesopores and narrow micropores. These activated carbons from olive-waste cakes showed a high capacity to adsorb herbicides (2,4-dichlorophenoxyacetic acid, 2,4-D; and 2-methyl, 4-chlorophenoxyacetic acid, MCPA) from water, with adsorption capacity values higher than those corresponding to a commercial activated carbon used from drinking water treatments.
Environmental Science and Technology 10/2002; 36(17):3844-3849. DOI:10.1021/es010305t · 5.48 Impact Factor