In this study, activated carbon derived from mangosteen peel (abbreviated as ACMP) was successfully fabricated. This as-prepared ACMP possessed graphite and had a porous structure with a specific surface area of 419.8554 m2/g. Investigations of the influencing factors on the ciprofloxacin (CIP) adsorption capability of the ACMP based on the static adsorption method showed that: adsorption equilibrium can be achieved in 60 min, the optimal pH for CIP adsorption was a pH of 6, and the optimal ratio between the material mass and solution volume was 3 g/L. The CIP adsorption process of the ACMP follows the Langmuir, Freundlich, Tempkin, Elovich, and Redlich–Peterson isotherm adsorption models. The maximum adsorption capacity calculated according to the Langmuir isothermal adsorption model for the CIP of the ACMP was (qmax = 29.76 mg/g). The CIP adsorption process of the ACMP followed the apparent quadratic kinetic equation, as well as spontaneous, endothermic, physical, and chemical adsorption. The adsorption rate was governed by membrane diffusion.

For the first time, activated carbon from a durian shell (ACDS) activated by H2SO4 was successfully synthesized in the present study. The fabricated ACDS has a porous surface with a specific surface area of 348.0017 m2·g−1, average capillary volume of 0.153518 cm3·g−1, the average pore diameter of 4.3800 nm; ash level of 55.63%; humidity of 4.74%; density of 0.83 g·cm−3; an iodine index of 634 mg·g−1; and an isoelectric point of 6.03. Several factors affecting Methylene Blue (MB) adsorption capacity of ACDS activated carbon was investigated by the static adsorption method, revealing that the adsorption equilibrium was achieved after 90 min. The best adsorbent pH for MB is 7 and the mass/volume ratio is equal to 2.5 g·L−1. The MB adsorption process of ACDS activated carbon follows the Langmuir, Freundlich, Tempkin, and Elovich isotherm adsorption model, which has determined the maximum adsorption capacity for MB of ACDS as qmax = 57.47 mg·g−1. The MB adsorption process of ACDS follows the of pseudo-second-order adsorption kinetic equation. The Weber and Morris Internal Diffusion Model, the Hameed and Daud External Diffusion Model of liquids have been studied to see if the surface phase plays any role in the adsorption process. The results of thermodynamic calculation of the adsorption process show that the adsorption process is dominated by chemical adsorption and endothermic. The obtained results provide an insight for potential applications of ACDS in the treatment of water contaminated by dyes.

The coal gasification wastewater figures prominently among types of industrial effluents due to its complex and phenolic composition, posing great difficulty for conventional water treatment processes. Since the coking wastewater is toxic and mutagenic to humans and animals, treatment of coal gasification wastewater is genuinely necessary. In this study, we established a lab-scale A2O (Anaerobic-Anoxic—Oxic) with moving bed biological reactor (MBBR) system and evaluated some water indicators of wastewater pretreated with internal electrolysis, of wastewater output of the established A2O-MBBR system, and of the wastewater treated by the combination thereof. The wastewater was taken from a coking plant at Thai Nguyen Iron and Steel Joint Stock Company in Vietnam. COD, BOD5, NH4+-N, phenol, and pH of the input coal gasification wastewater were 2359, 1105, 319, 172 mg/L, and 8 ± 0.1, respectively. The conditions of internal electrolysis were as follows: 720 min of reaction time, pH = 4, 25 g/L Fe-C dosage, and 100 mg/L PAM dosage. After internal electrolysis process, the removal of COD, BOD5, NH4+-N, and phenol were 53.7%, 56.7% 60.5%, and 73.3%, respectively. After 24 h of treatment, the treatment efficiencies of the combined treatment process are as follows: 100% phenol removal, 71.3% of TSS removal; 97.7% reduction of BOD5, and 97.1% reduction of COD; total N content reduced by 97.6%; total P content decreased by 81.6%; and NH4+-N content decreased by 97.5%. All above indicators after treatment have met QCVN 52: 2017/BTNMT (column A) Vietnamese standard for steel industry wastewater.

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The ciprofloxacin (CIP) removal ability of a Fe-Cu electrolytic material was examined with respect to pH (2–9), time (15–150 min), shaking speed (100–250 rpm), material mass (0.2–3 g/L), temperature (298, 308, 323) and initial CIP concentration (30–200 mg/L). The Fe-Cu electrolytic materials were fabricated by the chemical plating method, and Fe-C materials were mechanically mixed from iron powder and graphite. The results show that at a pH value of 3, shaking time 120 min, shaking speed 250 rpm, a mass of Fe-Cu, Fe-C material of 2 g/L and initial CIP concentration of 203.79 mg/L, the CIP removal efficiency of Fe-Cu material reached 90.25% and that of Fe-C material was 85.12%. The removal of CIP on Fe-Cu and Fe-C materials follows pseudo-first-order kinetics. The activation energy of CIP removal of Fe-Cu material is 14.93 KJ/mol and of Fe-C material is 16.87 KJ/mol. The positive ΔH proves that CIP removal is endothermic. A negative entropy of 0.239 kJ/mol and 0.235 kJ/mol (which is near zero and is also relatively positive) indicated the rapid removal of the CIP molecules into the removed products.