New System for Efficient Removal of Lignin with a High Proportion of Chlorine Dioxide

Abstract

Chlorine dioxide is used extensively as the bleaching agent in the clean pulp bleaching process. To further improve the efficiency of chlorine dioxide delignification, this study discusses the effect of a new system of a high proportion of chlorine dioxide on lignin removal. When the mass ratio of chlorine dioxide to lignin was 4 in this system, 50% of lignin was removed in a short time. To optimize the new bleaching system, the effects of temperature and pulp consistency on the new system were studied. The ratio of lignin removed was 50% when the reaction time was 30 min, temperature was 25 °C, and the pulp consistency was 5%. Compared with traditional chlorine dioxide bleaching, high proportion of chlorine dioxide bleaching can shorten the reaction time by 50%, reduce the reaction temperature to 25 °C, and greatly reduce energy consumption and adsorbable organic halogen (AOX) production by 45%. The new system provides a novel idea for clean bleaching of pulp.

Online Lifecycle Operating Costs Minimization Strategy for Fuel Cell Buses Considering Power Sources Degradation

“…The battery plays the role of peak-shaving and valley-filling in vehicle operation. The battery modeling uses the classical R-int model, and the battery current can be expressed as [29]…”

“…The battery plays the role of peak‐shaving and valley‐filling in vehicle operation. The battery modeling uses the classical R‐int model, and the battery current can be expressed as [ 29 ] where V oc and R bat are the open circuit voltage and internal resistance of the battery, and P bat denotes the battery power.…”

“…Figure 5 shows the performance differences between each control strategy when the SOH of both the fuel cell and battery is 1. Figure 5a depicts the standard cycle operating conditions constructed using Markov chain and real vehicle driving data, with an operating time of 3600 s. [ 29 ] The operating time consists of 830 s of congestion conditions, 1033 s of normal operating conditions, and 1737 s of smooth operating conditions, with average speeds of 7, 13.74, and 22.67 km h −1 . These average speeds align with real‐world vehicle operations.…”

A Review on Adsorbable Organic Halogens Treatment Technologies: Approaches and Application

“…Chlorine dioxide Pulp and paper industry wastes [57] Electrochemical Electrocoagulation and electrooxidation of dye using carbon steel anode Dye wastewater [147] Electrocoagulation using aluminum and stainless-steel electrodes Dye wastewater [148] Bio-electrochemical reactor (BER) Pharmaceutical wastes [115] Electrocoagulation Wastewaters from paper and pulp industry [149] Electrooxidation on Ti/TiO 2 -RuO 2 -IrO 2 electrode Phenol-formaldehyde resin manufacturing, oil refinery and bulk drug manufacturing industries wastes [150] Electrooxidation on Ti/SnO 2 /PdO 2 /RuO 2 (SPR) Tannery wastes [151] Electrooxidation on RuO 2 coated titanium electrode Paper and pulp mill effluents [152] Electrogenerated hydroxyl radicals Pesticides [153] Direct cathodic reduction of the azo-chromophores Dye wastewaters [154] Electrochemical oxidation of reverse osmosis concentrate on boron-doped diamond anode Wastewaters, tramadol wastes [111,[155][156][157][158] Photo-assisted electrochemical degradation Textile wastes [159] Boron-doped diamond electrode and others Municipal wastewaters with AOI [83] Table 2. Cont.…”

“…[53][54][55][56]. To reduce AOX content in outgoing wastewaters it is necessary to remove the main source of AOX [57] or use bleaching agents that do not cause AOX formation, for example the elemental chlorine free (ECF) process [58][59][60]. According to [31], the concentration of AOX in pulp and paper wastes is in the range of 2.8-83.0 mg•L −1 .…”