Adsorptive removal of surfactant using dolochar: A kinetic and statistical modeling approach

Abstract

Disturbingly high rates of consumption of surfactants in household and industries have led to mark them as emerging contaminants in the environment. In the present work, removal of sodium dodecyl sulfate (SDS), an anionic surfactant, using an industrial waste (dolochar) was explored. The adsorbent material was characterized with the help of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Kinetic evaluation was performed using first, pseudo-first, second, and pseudo-second order models. Adsorption of SDS over dolochar was expressed best by pseudo-second order kinetic model with regression coefficient (R 2 ) of .99. Three input parameters including adsorbent dose (20-10 g/L), initial concentration (30-100 mg/L) of the surfactant, and contact time (2-60 min) were chosen for optimization using response surface methodology based on Box-Behnken design (BBD) approach. A total of 15 experiments were run to examine the effect of these variables on removal of SDS by dolochar in a multivariate system. A regression analysis indicated the experimental data fitted well to a quadratic polynomial model with coefficient of regression (R 2 ) as .99. ANOVA and lack-of-fit test depicted the precision and efficiency of the model. The optimized conditions for SDS removal were found to be adsorbent dose 16.62 g/L, contact time 40 min, and initial concentration 47 mg/L with removal efficiency as 98.91%. © 2019 Water Environment Federation • Practitioner points• Daily ablutions and use of personal care products introduce a number of surfactants and recalcitrant compounds into the environment. • Adsorption is a handy and easy to operate treatment technique to remove graywater pollutants. • Kinetic and statistical modeling may be recommended as one of the most prominent tools to understand the removal mechanism. • Decentralized treatment of graywater using industrial wastes is recommended as sustainable solution in the developing nations.• Key words adsorption; Box-behnken design; dolochar; response surface methodology; surfactant

Greywater Treatment of Emerging Pollutant Linear Alkylbenzene Sulfonate By Adsorption With Leather Shave Waste Activated Carbon

“…After this time, the adsorption density smoothes, indicating a gradual adsorption. Shami et al (2020) observed a similar effect on the adsorption of surfactant sodium dodecyl sulfate on dolochar, and observed that these two steps represent that boundary layer diffusion can be considered the rate-limiting step in the initial adsorption phase and intraparticle diffusion is the rate limiting step in the final step. Although the models indicate a lower adsorption capacity in equilibrium for the temperature of 45 °C, the constants K1 and K2 are higher for this temperature, which represents a fast adsorption in the initial moments of contact between the adsorbent and the adsorbate, indicating high mass transfer rate.…”

Optimasi pH dan Konsentrasi Elektrolit dalam Elektrokoagulasi Limbah Surfaktan

“…Berbagai proses pengolahan atau pemisahan surfaktan dalam limbah telah dilakukan, diantaranya dengan adsorpsi menggunakan berbagai adsorben seperti bahan komposit MCM-41 (Ariapad, 2012), karbon aktif (Bindes, 2015), adsorben dolochar (Shami, 2019), menggunakan proses oksidasi O3/UV/H2O2 (Arslan, 2017), menggunakan metode gabungan koagulasi/flokulasi/sedimentasi dengan membran (Nascimento, 2019) dan menggunakan reaktor membran aerobik termofilik (Collivignarelli, 2019). Pada penelitian ini digunakan metode elektrokoagulasi pada proses pengolahan limbah simulasi surfaktan yang dilanjutkan dengan pengukuran kadar surfaktan secara spektroforometer.…”